19 Feb
2010
19 Feb
'10
1:18 p.m.
On 2/19/10, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I've done both. I've personally never had mechanical stability
problems with protoboards, but then I don't tend to wedge in 0.1"
header pins into my boards. I insert ICs, 1/4W resistors, various
capacitors, wires, crystals, LEDs and such, but rarely do I insert
header pins. I've always felt that they were "too large", even though
I know lots of people stuff them in there all the time.
Indeed. Quite distinctive.
I have read about the 68012, but don't think I've seen one in the wild.
It does. The difference isn't onerous - at least starting with
AmigaDOS 1.2 if not 1.1 (not sure about 1.0), you could upgrade your
68000 to a 68010 for an approximate 5% effective speed "boost" - this
was entirely due to the one-instruction DBcc "loop-mode cache" in
random places in the OS and in applications. As long as your
applications didn't try to execute any "MOVE from SR" instructions
(http://www.cpu-world.com/CPUs/68010/), no changes were required. If
you _did_ have some apps that did that, there a trap handler for that
on, IIRC, an early Fish disk. It would catch the privilege exception,
grab the status/condition code value and return the value to the
trapping instruction.
One app that was used to tell if you had the patch applied was the
AmigaDOS 1.1 calculator. With AmigaDOS 1.2, the app made an OS call
to get the required value. The older app used a "forbidden
instruction" so it made a good test.
If you are rolling your own OS or writing embedded code, it's not
really that hard to determine what size of stack frame you'll have and
handle both. I was responsible for replacing 68000s with 68010s in
the final COMBOARD product (partially to take advantage of "loop mode"
when dumping buffers across the DMA interface, increasing the block
speed of the board with a $50 chip). I don't think the code changes
relating to the 68010 took me more than part of an afternoon to
implement.
It's good to remember that it's so, but rather easy to accomplish once
you are that deep in the code.
-ethan
Yes, I have
been using breadboards for more than 20 years and never
had a problem with them. Sure, you must not try to stick thick wires
I must have been unlucky. I tried several of them in my younger days
(Eurobreadboars, the CSC/GSC Protoboards, etc) and had no end of
problems. In the end I started just soldering upo the circuits on
stripboard, and my desigens started working first time. [1] The local pound shop (a similar concept to dollar
stores) was selling
a camping lamp with 24 white LEDs for a pound.
I'd buy that for a pound! (and repurpose it, as you have).
BTW, the
article says it is an MC68008, so you did not need to count
24 pins (on one side) :-)
Oh, I didn't . I noticed it was a 0.6" wide package. The 68000 and 68010
DIL packages are 0.9" wide. The 68010 is
pin compatible to the 68000, but if you are in OS stuff,
Indeed. There is also a PGA version of the 68010, which is used in some
HP machines IIRC there's a 68012 which had more addres mins bought out,
but otherwise had the same PGA pinout you have to
modify some software if you are handling stack frames.
Those are not identical on the 68000 and 68010.
IIRC, the 68010 pushes more onto the stack on an interrupt. 
19 Feb
19 Feb
2:46 p.m.
From: "Ethan Dicks" <ethan.dicks at gmail.com>
Sent: Friday, February 19, 2010 10:18 PM
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Solderless breadboarding (and 68010 vs 68000)
On 2/19/10, Tony Duell <ard at
p850ug1.demon.co.uk> wrote:
Indeed. Quite distinctive.
Yes, the 68000 and 68010 are almost as impressive as the J11 :-)
Yes, I
have been using breadboards for more than 20 years and never
had a problem with them. Sure, you must not try to stick thick wires
... ... ...
BTW, the article says it is an MC68008, so you
did not need to count
24 pins (on one side) :-)
Oh, I didn't . I noticed it was a 0.6" wide package. The 68000 and 68010
DIL packages are 0.9" wide. >> The 68010 is pin compatible to the 68000, but
if you are in OS stuff,
>
> Indeed. There is also a PGA version of the 68010, which is used in some
> HP machines IIRC there's a 68012 which had more addres mins bought out,
> but otherwise had the same PGA pinout
I have a 10 MHz PGA 68000 somewhere IIRC.
I have read about the 68012, but don't think
I've seen one in the wild.
Me neither.
>> you have to modify some software if you are
handling stack frames.
>> Those are not identical on the 68000 and 68010.
>
> IIRC, the 68010 pushes more onto the stack on an interrupt.
Yes, it pushes a few more bytes to save the CPU state for recovery.
It does. The difference isn't onerous - at least
starting with
AmigaDOS 1.2 if not 1.1 (not sure about 1.0), you could upgrade your
68000 to a 68010 for an approximate 5% effective speed "boost" - this
was entirely due to the one-instruction DBcc "loop-mode cache" in
random places in the OS and in applications. As long as your
applications didn't try to execute any "MOVE from SR" instructions
(http://www.cpu-world.com/CPUs/68010/), no changes were required. If
you _did_ have some apps that did that, there a trap handler for that
on, IIRC, an early Fish disk. It would catch the privilege exception,
grab the status/condition code value and return the value to the
trapping instruction.
And for that 2-instruction cache I upgraded from 68000 to 68010 in my
StarShip. It has a tiny OS for start/stop/suspend/resume tasks and some
synchronization mechanisms (semaphore and timed-wait). The ship's code
runs in User space and the OS in Privileged space, so when a task gives
up the CPU it was via a TRAP.
One app that was used to tell if you had the patch
applied was the
AmigaDOS 1.1 calculator. With AmigaDOS 1.2, the app made an OS call
to get the required value. The older app used a "forbidden
instruction" so it made a good test.
I never thought of using a forbidden instruction, so I changed the code from
68000 to 68010. The test and then processing the stack frame accordingly
is clever, but would cause performance drop. May more than was to be
gained by the 2-instruction caching. I don't know.
If you are rolling your own OS or writing embedded
code, it's not
really that hard to determine what size of stack frame you'll have and
handle both. I was responsible for replacing 68000s with 68010s in
the final COMBOARD product (partially to take advantage of "loop mode"
when dumping buffers across the DMA interface, increasing the block
speed of the board with a $50 chip). I don't think the code changes
relating to the 68010 took me more than part of an afternoon to
implement.
Yeah, if you know the CPU at the assembler level, a few hours work is
what it takes :-) I've done that. I hope to put some new life into my
StarShip
later this year and brush up the 68000/68020 assembler knowledge. It's
5 years ago and I have plenty of ideas to code :-) Will be fun and looking
forward to that too!
It's good to remember that it's so, but rather
easy to accomplish once
you are that deep in the code.
Indeed.
- Henk.
20 Feb
20 Feb
11:28 a.m.
[1] The local
pound shop (a similar concept to dollar stores) was selling
a camping lamp with 24 white LEDs for a pound.
I'd buy that for a pound! (and repurpose it, as you have). BTW, the
article says it is an MC68008, so you did not need to count
24 pins (on one side) :-)
Oh, I didn't . I noticed it was a 0.6" wide package. The 68000 and 68010
DIL packages are 0.9" wide. I have read about the 68012, but don't think
I've seen one in the wild.
Nor have I. I've net seen a full data sheet on it either. Some HP9000/200
machines (the -U models and the 9817) use a PGA-packaged 68010, and 27
(rather than 23) address lines go from the socket to the MMU circuitry.
I've always assumed this is for a 68012 processor. I'd like to find one
and try it, if onl;y to see if the '68010 Processor' messge in the
power-on tests changes.
-tony
22 Feb
22 Feb
11:34 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On Sat, 20 Feb 2010 19:28:08 +0000 (GMT)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
Incidentally, I was amazed how little current a white
LED needs to give
some glow.
The Cree XP-G gets up to 140 Lumen at 1 Watt. It can be driven with
3 Watts i.e. 1 A current but efficiency will drop. So it gets "only"
around 350 Lumen at 3 Watt. I have some of those LEDs. They emit so
much light that it will burn your finger when you touch the top of the
LED. This is only caused by the energy of the light that gets absorbed
by the skin. The LEDs stays cool. (OK. They are mounted on a big heat
sink.)
Nichia has low power LEDs that achieve up to 150 Lumen per Watt.
White LEDs have become one of the most efficient light sources.
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
11:47 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On 22 Feb 2010 at 20:34, Jochen Kunz wrote:
White LEDs have become one of the most efficient light
sources.
Is that really true? I would have suspected that red LEDs would be
far more efficient in terms of lumens-per-watt. The drawback being
that they're monochromatic.
--Chuck
1:35 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On Mon, Feb 22, 2010 at 11:47:10AM -0800, Chuck Guzis wrote:
On 22 Feb 2010 at 20:34, Jochen Kunz wrote:
What works in favour of the white LEDs is that everybody has been
working _real_ hard to get their output _way_ up. For the other colors,
the pressure for more light isn't that intense.
Although by now the LED light output in general is high enough that they
are used in traffic lights (a lot of the traffic lights around here
(Zurich) use LEDs).
Regards,
Alex.
--
"Opportunity is missed by most people because it is dressed in overalls and
looks like work." -- Thomas A. Edison
White LEDs have become one of the most efficient
light sources.
Is that really true? I would have suspected that red LEDs would be
far more efficient in terms of lumens-per-watt. The drawback being
that they're monochromatic. 
2:04 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
Alexander Schreiber wrote:
Although by now the LED light output in general is
high enough that they
are used in traffic lights (a lot of the traffic lights around here
(Zurich) use LEDs).
Regards,
Alex.
For what it's worth, I'd imagine most cities either already have, or are
starting to use LED traffic lights. We have had LED traffic lights in
Pittsburgh, Pennsylvania, USA for at least a couple years. I might even
be willing to bet that most(all?) new lights installed around here are LED.
Keith
3:16 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On Feb 22, 2010, at 5:04 PM, Keith wrote:
I see incandescent traffic lights every once in a while, but rarely. Most everything
I've seen for the past few years is LED.
-Dave
--
Dave McGuire
Port Charlotte, FL
Although by
now the LED light output in general is high enough that they
are used in traffic lights (a lot of the traffic lights around here
(Zurich) use LEDs).
Regards,
Alex.
For what it's worth, I'd imagine most cities either already have, or are starting
to use LED traffic lights. We have had LED traffic lights in Pittsburgh, Pennsylvania,
USA for at least a couple years. I might even be willing to bet that most(all?) new
lights installed around here are LED. 
4:42 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
Dave McGuire wrote:
On Feb 22, 2010, at 5:04 PM, Keith wrote:
I see incandescent traffic lights every once in a while, but rarely. Most
everything I've seen for the past few years is LED.
I see quite a few incandescents up here in northern MN still; it's rumored
that the harsh winters cause problems with the LED ones - they just don't
output enough heat, so snow and ice can build up and obscure them.
Maybe the current generation have built-in heaters to combat this (which still
doesn't make them pointless, I suppose, as LEDs should need far less 'bulb
changes')
cheers
Jules
Although
by now the LED light output in general is high enough that
they are used in traffic lights (a lot of the traffic lights around
here (Zurich) use LEDs). Regards, Alex.
For what it's worth, I'd imagine
most cities either already have, or are
starting to use LED traffic lights. We have had LED traffic lights in
Pittsburgh, Pennsylvania, USA for at least a couple years. I might even
be willing to bet that most(all?) new lights installed around here are
LED. 
24 Feb
24 Feb
4:51 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
Jules Richardson wrote:
I see quite a few incandescents up here in northern MN
still; it's
rumored that the harsh winters cause problems with the LED ones - they
just don't output enough heat, so snow and ice can build up and obscure
them.
... So put heaters in them to keep the lenses warm in winter! :)
(it only has to go a few degrees above zero... shouldn't take that much
power if it's on a time-limited thermostat)
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/
5:10 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
From: classiccmp at philpem.me.uk
Jules Richardson wrote:
Heating water one degree = 1 calorie per cu-centimeter
Heating Ice one degree = 80 calorie per cu-centimeter
Melting ice takes a lot of power.
Dwight
_________________________________________________________________
Hotmail: Free, trusted and rich email service.
http://clk.atdmt.com/GBL/go/201469228/direct/01/
I see quite a few incandescents up here in
northern MN still; it's
rumored that the harsh winters cause problems with the LED ones - they
just don't output enough heat, so snow and ice can build up and obscure
them.
... So put heaters in them to keep the lenses warm in winter! :)
(it only has to go a few degrees above zero... shouldn't take that much
power if it's on a time-limited thermostat)
--
Phil.
5:13 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
From: dkelvey at hotmail.com
To: cctalk at classiccmp.org
Subject: RE: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
Date: Wed, 24 Feb 2010 17:10:53 -0800
Oooops!!! meaning melting
ice
Dwight
From: classiccmp at philpem.me.uk
Jules Richardson wrote:
Heating water one degree = 1 calorie per cu-centimeter
Heating Ice one degree = 80 calorie per cu-centimeter I see quite a few incandescents up here in
northern MN still; it's
rumored that the harsh winters cause problems with the LED ones - they
just don't output enough heat, so snow and ice can build up and obscure
them.
... So put heaters in them to keep the lenses warm in winter! :)
(it only has to go a few degrees above zero... shouldn't take that much
power if it's on a time-limited thermostat)
--
Phil.
Melting ice takes a lot of power.
Dwight
_________________________________________________________________
Hotmail: Free, trusted and rich email service.
http://clk.atdmt.com/GBL/go/201469228/direct/01/
_________________________________________________________________
Hotmail: Free, trusted and rich email service.
http://clk.atdmt.com/GBL/go/201469228/direct/01/
25 Feb
25 Feb
8:59 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
Philip Pemberton wrote:
Jules Richardson wrote:
Hence the: "Maybe the current generation have built-in heaters to combat this"
bit ;-) I don't know if they actually do that, at least not yet. I expect it
takes time to come up with a design (the easy bit) and then get it approved
for actual use (lots of testing and paperwork, no doubt)
cheers
Jules
I see quite a few incandescents up here in
northern MN still; it's
rumored that the harsh winters cause problems with the LED ones - they
just don't output enough heat, so snow and ice can build up and
obscure them.
... So put heaters in them to keep the lenses warm in winter! :)
(it only has to go a few degrees above zero... shouldn't take that much
power if it's on a time-limited thermostat)
22 Feb
22 Feb
2:10 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On 22 Feb 2010 at 22:35, Alexander Schreiber wrote:
Although by now the LED light output in general is
high enough that
they are used in traffic lights (a lot of the traffic lights around
here (Zurich) use LEDs).
I see them in tailights for buses and trucks also. They have a
somewhat different color (narrower spectral distribution) than
filtered incandescent lamps.
Initially, I mystified my wife by being able to pick out LED
stoplights from several blocks distance. I'm very sensitive (for
some unknown reason) to flicker and those line-powered traffic lights
evidently were pretty high on ripple. More recent ones don't display
that effect, so the power supplies must have improved.
However, to my eye, the biggest abomination are cheap Christmas tree
LED lights with very pronouced flicker. I haven't researched it, but
I suspect that the LEDs in such strings are hooked in series and used
to self-rectify the line current.
I picked up a couple of strings last month at the local "dollar"
store--they're GE-branded. Come Christmas, I run them off of a nice
filtered DC supply--or at least a full-wave bridge.
--Chuck
3:57 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On Mon, Feb 22, 2010 at 02:10:43PM -0800, Chuck Guzis wrote:
On 22 Feb 2010 at 22:35, Alexander Schreiber wrote:
The local trains also have some locomotives with LED clusters for tail
and front lights (but they also have incandescent front lights as well).
Although by now the LED light output in general
is high enough that
they are used in traffic lights (a lot of the traffic lights around
here (Zurich) use LEDs).
I see them in tailights for buses and trucks also. They have a
somewhat different color (narrower spectral distribution) than
filtered incandescent lamps.
Initially, I mystified my wife by being able to pick out LED
stoplights from several blocks distance. I'm very sensitive (for
some unknown reason) to flicker and those line-powered traffic lights
evidently were pretty high on ripple. More recent ones don't display
that effect, so the power supplies must have improved.
However, to my eye, the biggest abomination are cheap Christmas tree
LED lights with very pronouced flicker. I haven't researched it, but
I suspect that the LEDs in such strings are hooked in series and used
to self-rectify the line current.
Those have been popping up around here with a vengeance. You can usually
pick them out by color alone: really _white_ instead of the yellow to
yellowish white you tend to get with incandescents.
I've also seen decorative light lines on at least one of the Zuerisee
passenger ships here: It's got to be LED since it
a) changes color
b) has very "clean" colors, the typical narrow spectrum of LEDs
Regards,
Alex.
--
"Opportunity is missed by most people because it is dressed in overalls and
looks like work." -- Thomas A. Edison
4:49 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On 22/02/2010 22:10, Chuck Guzis wrote:
On 22 Feb 2010 at 22:35, Alexander Schreiber wrote:
All the traffic lights here have been LEDs for several years. I also
see them in tail lights of cars and other vehicles. A few years ago,
the law for bicycle lights was changed to make LEDs legal (it used to
specify a certain wattage of 6V bulb, which now seems pretty silly given
the way intensity varies a lot with small voltage changes).
--
Pete Peter Turnbull
Network Manager
University of York
Although by now the LED light output in general
is high enough that
they are used in traffic lights (a lot of the traffic lights around
here (Zurich) use LEDs).
I see them in tailights for buses and trucks also. They have a
somewhat different color (narrower spectral distribution) than
filtered incandescent lamps. 
5:14 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
There was some interesting news on the LED traffic lights and the recent winter storms.
Apparently they don't melt off the snow like the incandescents did. They are talking
about putting heaters back in the lights.
Date: Tue, 23 Feb 2010 00:49:13 +0000
From: pete at dunnington.plus.com
To:
Subject: Re: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On 22/02/2010 22:10, Chuck Guzis wrote:
_________________________________________________________________
Hotmail: Trusted email with powerful SPAM protection.
http://clk.atdmt.com/GBL/go/196390707/direct/01/
On 22 Feb 2010 at 22:35, Alexander Schreiber
wrote:
All the traffic lights here have been LEDs for several years. I also
see them in tail lights of cars and other vehicles. A few years ago,
the law for bicycle lights was changed to make LEDs legal (it used to
specify a certain wattage of 6V bulb, which now seems pretty silly given
the way intensity varies a lot with small voltage changes).
--
Pete Peter Turnbull
Network Manager
University of York Although by now the LED light output in general
is high enough that
they are used in traffic lights (a lot of the traffic lights around
here (Zurich) use LEDs).
I see them in tailights for buses and trucks also. They have a
somewhat different color (narrower spectral distribution) than
filtered incandescent lamps. 
5:21 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On Mon, 22 Feb 2010, Randy Dawson wrote:
Apparently they don't melt off the snow like the
incandescents did.
They are talking about putting heaters back in the lights.
It wouldn't take very much heat; there might be room to add an
incandescent bulb into the housing to generate the needed heat. I
understand that the incandescent bulbs that they have are available to be
"repurposed" since they changed to LEDs.
23 Feb
23 Feb
11:27 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
I see them in tailights for buses and trucks also.
They have a
somewhat different color (narrower spectral distribution) than
filtered incandescent lamps.
LED clusters are very common as lights on buses in London. In fact the
first place I saw white LEDs being used was the reversing light of a bus.
The turn indicators (cluster of yellow LEDs) have a curious property.
When they turn off, one LED stays on for considerably (1s or so) longer
than all the others. It's the same LED on all indicators, so it must be a
design feature, but I wonder what the reason is.
I've also seen al LED Belisha Beacon (this is a flashing yellow sphere on
top of a pole, used to indicate the location of a pedestrian crossing in
England). The LED verson had a non-illuminated yellow sphere with a
vertical circle of yellow LEDs around it (a sort-of halo). I guess that
since such things turn on and off all the time, the GLS bulbs used in the
traditional type have a fairly short life. LEDs whould last a lot longer.
[...]
However, to my eye, the biggest abomination are cheap
Christmas tree
LED lights with very pronouced flicker. I haven't researched it, but
I suspect that the LEDs in such strings are hooked in series and used
to self-rectify the line current.
I would hope not. The maximum revers voltage for most LEDs is quite low.
What is more normal is to put a silicon diode in inverse parallel (and
fit a suitable limiting resistor in sereis with the pair). This fo course
means that LED flickers at mains frequency (rather than twice it as with
normal bulbs) and when I was experimenting with my white LED strobe, I
could certainly notice the flicker at 50Hz (and probably at 60Hz).
I picked up a couple of strings last month at the local "dollar"
store--they're GE-branded. Come Christmas, I run them off of a nice
filtered DC supply--or at least a full-wave bridge.
You mean you're not going to modify them to have individual control of
the LEDs and them run them off a classic computer?
-tony
12:15 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On Feb 23, 2010, at 2:27 PM, Tony Duell wrote:
I've heard lots of people talk about how disconcerting the abrupt
turn-off of "those weird new traffic lights" is. I'll bet that has
something to do with it.
-Dave
--
Dave McGuire
Port Charlotte, FL
I see them in
tailights for buses and trucks also. They have a
somewhat different color (narrower spectral distribution) than
filtered incandescent lamps.
LED clusters are very common as lights on buses in London. In fact the
first place I saw white LEDs being used was the reversing light of
a bus.
The turn indicators (cluster of yellow LEDs) have a curious property.
When they turn off, one LED stays on for considerably (1s or so)
longer
than all the others. It's the same LED on all indicators, so it
must be a
design feature, but I wonder what the reason is.
5:33 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On 23 Feb 2010 at 19:27, Tony Duell wrote:
According to
http://www.muanalysis.com/publications/Quantum-Wells-in-Seasonal-
Department-Christmas-Lights-LED.pdf
the 70-LED strings get by with a resistor only. The 100 LED strings
appear to use a diode. Heaven forfend that a diode bridge be used
for them--that could cost additional cents per string.
There's some fellow on the web who's been making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
--Chuck
However, to my
eye, the biggest abomination are cheap Christmas tree
LED lights with very pronouced flicker. I haven't researched it,
but I suspect that the LEDs in such strings are hooked in series and
used to self-rectify the line current.
I would hope not. The maximum revers voltage for most LEDs is quite
low. 
6:14 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Chuck Guzis wrote:
There's some fellow on the web who's been
making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
I have on occasion run single LEDs from line voltage by paralleling the LED
with a diode, then putting the pair in series with a C and R. C is calculated
to provide most of the voltage drop via capacitive reactance, a small R is
still present to limit inrush current. The diode limits the reverse voltage and
permits bidirectional current flow so the cap sees AC.
Power consumption and heat dissipation are reduced compared to a solution using
only R, and a power resistor is not needed.
I haven't tested the circuit over many on/off cycles though, to find out
whether perhaps the peak in-rush current reduces LED life.
9:34 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On Feb 23, 2010, at 9:14 PM, Brent Hilpert wrote:
Wow...that's pretty impressive work! Elegant in its simplicity.
-Dave
--
Dave McGuire
Port Charlotte, FL
There's
some fellow on the web who's been making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
I have on occasion run single LEDs from line voltage by paralleling
the LED
with a diode, then putting the pair in series with a C and R. C is
calculated
to provide most of the voltage drop via capacitive reactance, a
small R is
still present to limit inrush current. The diode limits the reverse
voltage and
permits bidirectional current flow so the cap sees AC.
Power consumption and heat dissipation are reduced compared to a
solution using
only R, and a power resistor is not needed.
I haven't tested the circuit over many on/off cycles though, to
find out
whether perhaps the peak in-rush current reduces LED life.
10:07 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On 24 Feb 2010 at 0:34, Dave McGuire wrote:
I remember a code-practice oscillator circuit that was line-powered a
long time ago. It used a 6SL7 twin triode, with one section
operating as a rectifier and the other, as the oscillator. The
curious thing was that the filament of the 6SL7 was powered off of
line voltage connected through a 1 uF non-polarized oil-paper
capacitor. I actually built one--it worked just fine, particularly
if you took care to ensure that the chassis wasn't live.
It may have come out of an old receiving tube manual or ARRL
handbook; I don't recall--and I hope I have the details correct.
Someone will doubtless turn up that it used a 6SQ7 or 6X8 or some
such variation.
--Chuck
Power
consumption and heat dissipation are reduced compared to a
solution using only R, and a power resistor is not needed. I haven't
tested the circuit over many on/off cycles though, to find out
whether perhaps the peak in-rush current reduces LED life.
Wow...that's pretty impressive work! Elegant in its simplicity.
24 Feb
24 Feb
1:18 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
I remember a code-practice oscillator circuit that was
line-powered a
long time ago. It used a 6SL7 twin triode, with one section
operating as a rectifier and the other, as the oscillator. The
IIRC, there were American valves (perhaps I should say tubes :-)) that
contained a half-wave rectifier and an audio autput pentode in one
envelope. The number 70L7 springs to mind, but I am not well up in US
valve numbers.
They were desinged for use (in the obvious way) in lo-fi record playes (a
crystal pickup cartridge would give enough signal to drive the pentode
section).
I am suprised your conde practice oscillator didn't use one of those.
curious thing was that the filament of the 6SL7 was
powered off of
line voltage connected through a 1 uF non-polarized oil-paper
capacitor. I actually built one--it worked just fine, particularly
if you took care to ensure that the chassis wasn't live.
Did it have haedphones as the audio output devices? If so, it only takes
one little insulation breakdown to turn it into a fair version of the
electric chair...
Antohter trick used over here in hybrid TV sets (using transistors for
the small-signal stages and valves in the output stages) was to put a
diode in series iwth the heater string. This reduced the dropping
resistor needed (and saved power). Often, the supply to the transistor
stages was taken from the bottom end of the heater string, using the
heaters as the dropping resistor for that supply.
Getting back to LEDs, I bought a cheap wall-wart polarity tester. It
conists of a couple of LEDs and limiting reistors wired to assorted power
connectors. The LED/resistor pairs are wired in inverse paralel, so one
lights for tip +ve, the other for tip -ve (and both light for an AC
wall-wart). But of course the LED that's not on gets the full wall-wort
output voltage applied to it backwards, which is not a good thing. I
modified miue by removing one of the resistors and adding a jumper wire
on the PCB so the LEDs were in inverse parallel, and thus each LED
limited the reverse voltage applied ot the other one. This must be one of
the few cheap products which can be improved by removing a component
-tony
2:01 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On 24 Feb 2010 at 21:18, Tony Duell wrote:
IIRC, there were American valves (perhaps I should say
tubes :-)) that
contained a half-wave rectifier and an audio autput pentode in one
envelope. The number 70L7 springs to mind, but I am not well up in US
valve numbers.
They were desinged for use (in the obvious way) in lo-fi record playes
(a crystal pickup cartridge would give enough signal to drive the
pentode section).
I am suprised your conde practice oscillator didn't use one of those.
Cost, mostly. Even at contemporary prices, the 6SL7 was far cheaper
and more common than a 70L7 or the more usual 117L7/M7/N7. The dual
triodes were part of most TV sets and a fair number of audio
amplifiers.
I remember some "universal" battery-line sets that used a 117Z3
rectifier to drop the line voltage and also to supply the filament
voltage for battery sets when run from the AC line. This was before
selenium rectifiers became common.
Did it have haedphones as the audio output devices? If
so, it only
takes one little insulation breakdown to turn it into a fair version
of the electric chair...
Yes, but it used a resistor as a plate load and a capacitor coupled
to the headphones. An interstage AF transformer would have been
much safer--but again, cost was an object.
If you were any kind of a scavenger, getting on the air meant at most
finding an old AM radio or two and a TV set. You could go to a swap
meet for transmitter crystals or beg one. A 6v 150 ma pilot lamp
would serve as an adquate plate current indicator. Coils could be
easily hand-wound.
--Chuck
10:22 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
I remember some "universal" battery-line
sets that used a 117Z3
rectifier to drop the line voltage and also to supply the filament
voltage for battery sets when run from the AC line. This was before
selenium rectifiers became common.
Yes, those directly-heated valves needed a DC fillament supply and before
metal (or semiconductor) rectifiers became common. about the only way to
get that from the mains was to use a dropping resistor from the HT (B+) line.
At least one set over here used a mains transformer and a full-wave valve
rectifier (I am thinking 'EZ40', which has a 6.3V heater and a B8A
'rimlock' base) to provide the HT (about 90V), with a series string of
filaments (7.5V totla) run from that via a dropping resistor in mains
mode. On batteries, of coursem it used separate 90V and 7.5V (!) dry
batteries.
Did it have haedphones as the audio output
devices? If so, it only
takes one little insulation breakdown to turn it into a fair version
of the electric chair...
Yes, but it used a resistor as a plate load and a capacitor coupled
to the headphones. An interstage AF transformer would have been
much safer--but again, cost was an object. If you were any kind of a scavenger, getting on the
air meant at most
finding an old AM radio or two and a TV set. You could go to a swap
Presumavly you wanted the line output valve ('sweep tube'?) from the
latter to use as the transmitter PA.
meet for transmitter crystals or beg one. A 6v 150 ma
pilot lamp
would serve as an adquate plate current indicator. Coils could be
easily hand-wound.
You mean it's all changed now? :-(
-tony
25 Feb
25 Feb
1:47 p.m.
New subject: OT: white LEDs
Tony Duell wrote:
Yep... Crystal Sets are all high-tech, looking at a Regen-kit a few weeks
back I got it is *still* cheap and low tech ( other than the 1T4 tubes).
See the hi-tech coils here.
http://makearadio.com/index.php
meet for
transmitter crystals or beg one. A 6v 150 ma pilot lamp
would serve as an adquate plate current indicator. Coils could be
easily hand-wound.
You mean it's all changed now? :-( -tony
The big thing it is not using a RF choke for regen, and I think
that is the biggest problem.The other thing I think it could
of had plug in-coil rather a fixed multi-tapped coil. Still parts
are cheap, and I can rebuild the design on pine board
with new ideas.I can take my time, since I have *No* AM stations
out here.
Ben.
2:04 p.m.
New subject: OT: white LEDs
On 25 Feb 2010 at 14:47, Ben wrote:
The big thing it is not using a RF choke for regen,
and I think
that is the biggest problem.The other thing I think it could
of had plug in-coil rather a fixed multi-tapped coil. Still parts are
cheap, and I can rebuild the design on pine board with new ideas.I can
take my time, since I have *No* AM stations out here.
Good grief, where do you live? There are days when I think I hear
Rush Limbaugh coming in through the fillings in my teeth. But I can
*see* the local transmitter antenna farm two ridges over.
It doesn't improve the programming quality, however.
--Chuck
2:37 p.m.
New subject: OT: white LEDs
Chuck Guzis wrote:
On 25 Feb 2010 at 14:47, Ben wrote:
Cold Lake, Alberta. About 200 km ( line of sight ) from the nearest
large city.
The big thing it is not using a RF choke for
regen, and I think
that is the biggest problem.The other thing I think it could
of had plug in-coil rather a fixed multi-tapped coil. Still parts are
cheap, and I can rebuild the design on pine board with new ideas.I can
take my time, since I have *No* AM stations out here.
Good grief, where do you live? There are days when I think I hear
Rush Limbaugh coming in through the fillings in my teeth. But I can
*see* the local transmitter antenna farm two ridges over. It doesn't improve the programming quality,
however.
Well would talk radio, improve the the tooth reception. :)
I tend to agree, AM radio has gone downhill, and FM now being commercial
has mostly *loud* something.
Ben.
--Chuck
BTW. I remember Giligains(sp) Island had a episode about a filling
being a radio.
2:01 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On 25 Feb 2010 at 6:22, Tony Duell wrote:
Presumavly you wanted the line output valve
('sweep tube'?) from the
latter to use as the transmitter PA.
Oh, much more than that--the radio was the source of variable
capacitors, but the TV was the treasure trove. A huge power
transformer, rectifier (usually something like a 5U4), filter caps,
horizontal output tube(s) (Some early sets used push-pull 6BG6s;
later ones just ran the horizontal output tube to within an inch of
its life. Plus ?a change...). The exciter could be a 6SJ7, from the
video output stage.
TV power transformers were very generous with filament windings and
the high-voltage winding was usually something on the order of 450-0-
450, so a fullwave bridge could be used to furnish plate voltage for
something much larger than the run-of-the-mill novice rig. Indeed,
there were hams who rewound TV transformers for high-power final
supplies.
Life in the trash heap was good...
--Chuck
26 Feb
26 Feb
11:26 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On 25 Feb 2010 at 6:22, Tony Duell wrote:
Ah, TV sets over here rarely had power transformers at all, and if they
did they were likely to be autotransformers. Every valved monochrome TV
Iv'e worked on (and most that I've seen the service sheets for) had a
300mA series string of valve heaters and got the B+ line by half-wave
rectifying the mains. The EHT came from the horizontal flyback, of
course, as did the 'boost supply', taken from the primary of the
horizontal output transformer. This was around twice the HT+ voltage (say
400V or so) and was used as the supply to the horizontal output stage and
sometimes other stages too.
Colour sets often had a mains transformer, but it wqs an autotransformer
for the HT+ and series-string heaters, with a separate 5.3V widnign for
the CRT heater only. Not a particulalrly useful part for homebrewing.
And of course out horizontal output valves had strange heater reatings
(300mA current, at 30-40V depending o nthe type IIRC). Again not too useful.
You were more likely to find a amins transformer in a large valve radio
(you's get 6.3V at 2 or 3A, 350-0-350V and often a separate 4V or 5V
winding for the rectifier heater). Of course later radios used
series-string heaters (often 100mA) and no transformer.
-tony
Presumavly you wanted the line output valve
('sweep tube'?) from the
latter to use as the transmitter PA.
Oh, much more than that--the radio was the source of variable
capacitors, but the TV was the treasure trove. A huge power
transformer, rectifier (usually something like a 5U4), filter caps,
horizontal output tube(s) (Some early sets used push-pull 6BG6s;
later ones just ran the horizontal output tube to within an inch of
its life. Plus =E7a change...). The exciter could be a 6SJ7, from the
video output stage.
1:33 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On Fri, Feb 26, 2010 at 2:26 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Ah, TV sets over here rarely had power transformers at
all... Every valved
monochrome TV Iv'e worked on... had a 300mA series string of valve heaters
and got the B+ line by half-wave rectifying the mains.
Sure, but your mains were twice the voltage of our mains.
-ethan
27 Feb
27 Feb
10:27 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On Fri, Feb 26, 2010 at 2:26 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I am suprised that voltage doubler PSUs (2 diodes, 2 capacitors) weren't
used in the States.
-tony
Ah, TV sets over here rarely had power
transformers at all... Every valved
monochrome TV Iv'e worked on... had a 300mA series string of valve heaters
and got the B+ line by half-wave rectifying the mains.
Sure, but your mains were twice the voltage of our mains.
11:02 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On 27 Feb 2010 at 18:27, Tony Duell wrote:
I am suprised that voltage doubler PSUs (2 diodes, 2
capacitors)
weren't used in the States.
To be sure, there were hot-chassis tube sets, but by and large, these
were the small ones made during the early-to-mid 60's. All of the
large (21" and larger), AFAIK--even the Muntz models--used power
transformers. A transformer out of an early color set was massive.
--Chuck
28 Feb
28 Feb
11:13 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Tony Duell wrote:
They were on occasion, but more so in black and white TVs. TMU, the greater B+
current requirements or quality expectations tended to rule them out for colour TVs.
In other instances of novel fulfilment of power supply requirements there were
really weird structures such as feeding another functional unit (some sync
processing say) from the otherwise-wasted energy in the class-A audio output
cathode bias resistor.
On Fri, Feb
26, 2010 at 2:26 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I am suprised that voltage doubler PSUs (2 diodes, 2 capacitors) weren't
used in the States. Ah, TV sets over here rarely had power
transformers at all... Every valved
monochrome TV Iv'e worked on... had a 300mA series string of valve heaters
and got the B+ line by half-wave rectifying the mains.
Sure, but your mains were twice the voltage of our mains.
11:42 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Tony Duell wrote:
They were on occasion, but more so in black and white TVs. TMU, the greater B+
I was thinking of monochrome TVs...
On Fri,
Feb 26, 2010 at 2:26 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I am suprised that voltage doubler PSUs (2 diodes, 2 capacitors) weren't
used in the States. Ah, TV sets over here rarely had power
transformers at all... Every valved
monochrome TV Iv'e worked on... had a 300mA series string of valve heaters
and got the B+ line by half-wave rectifying the mains.
Sure, but your mains were twice the voltage of our mains. current requirements or quality expectations tended to
rule them out for colour TVs.
In other instances of novel fulfilment of power supply requirements there were
really weird structures such as feeding another functional unit (some sync
processing say) from the otherwise-wasted energy in the class-A audio output
cathode bias resistor.
Ah yes, I seem to remember readint that was known as the 'stacked B+'
circuit.. You got some verry odd effects if the decoupling capacitor went
open-circuit...
At least one Philips tape recorder (I thick it was the 'upright' model
EL3514) used the bias voltage for the output pentode (which was used as
the bias/erase oscillator in record mode) as the filament supply for a
sub-miniature indicator valve (magic eye) -- I think it was a DM71 --
used to show the recording level.
-tony
9:07 p.m.
New subject: OT: white LEDs
Tony Duell wrote:
Doublers often were used in transformerless sets in the US, perhaps
almost always. ISTR seleniums with a gradual migration to solid state
diodes as they became available in the needed voltage ratings. At the
moment, I can't recall having seen vacuum tube diodes used in a TV
doubler, though I imagine there were instances of that. I still have a
little 14" B&W Motorola in the garage (with a bad CRT) that might not
have the doubler. If I ever find it again or the Sams for it I'll have
to check and see. Please keep in mind that I'm speaking from my
memories of TV repair in about the 1956 to 1960 area. Once I completed
college in 1960 my path led me to devices mostly containing those
mysterious devices with no filaments. :-)
Later,
Charlie C.
On Fri, Feb
26, 2010 at 2:26 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I am suprised that voltage doubler PSUs (2 diodes, 2 capacitors) weren't
used in the States.
-tony
Ah, TV sets over here rarely had power
transformers at all... Every valved
monochrome TV Iv'e worked on... had a 300mA series string of valve heaters
and got the B+ line by half-wave rectifying the mains.
Sure, but your mains were
twice the voltage of our mains.
1 Mar
1 Mar
11:41 a.m.
New subject: OT: white LEDs
Tony Duell wrote:
Doublers often were used in transformerless sets in the US, perhaps
almost always. ISTR seleniums with a gradual migration to solid state
Right. I am not suprised.
I have never seen the service manual or scheamtic for a valved US TV set.
Unlike radio sets (the AM broadcast band is pretty much the same in the
US and Europe, and if oyu want to recieve the European 'long wave' band,
it's a simple modification), the differnce in TV standards meant that
almost no US TVs ended up over here.
Wit hradios, the difference in mains voltage was often handled by an
aditional dropping resistor. This was commonly something called a 'line
cord' which was a piece of 2 core cable with one wire being resistance
wire (!). Needless to say shortening this (which some owners did for
neatness) was a bad idea... This line cord also ran hot, if left coiled up
it was afavourite plae for cats to sleep :-)
On Fri,
Feb 26, 2010 at 2:26 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I am suprised that voltage doubler PSUs (2 diodes, 2 capacitors) weren't
used in the States.
-tony
Ah, TV sets over here rarely had power
transformers at all... Every valved
monochrome TV Iv'e worked on... had a 300mA series string of valve heaters
and got the B+ line by half-wave rectifying the mains.
Sure, but your mains were
twice the voltage of our mains. diodes as they became available in the needed voltage
ratings. At the
moment, I can't recall having seen vacuum tube diodes used in a TV
Mopstof the UK monochrome vavled TVs I've worked on ued either a selenium
('metal' ) rectivfier or a silicon diode (BY127 or similar). There were
valve rectifiers (PY31, PY82), but they are much less common. Of course
our sets just used a simple half-wave rectifier from the 240V or so mains.
doubler, though I imagine there were instances of
that. I still have a
little 14" B&W Motorola in the garage (with a bad CRT) that might not
have the doubler. If I ever find it again or the Sams for it I'll have
to check and see. Please keep in mind that I'm speaking from my
memories of TV repair in about the 1956 to 1960 area. Once I completed
college in 1960 my path led me to devices mostly containing those
mysterious devices with no filaments. :-)
And now we have TVs with no filaments at all. LCD panels with CCFL
backlightes or plasma panes. I am not looking forward to having to repair
one of those things. BGA chips, etc. and yes, according to the service
manual foe the set we hae, you do do component-levle repair...
-tony
12:07 p.m.
New subject: OT: white LEDs
On 1 Mar 2010 at 19:41, Tony Duell wrote:
Wit hradios, the difference in mains voltage was often
handled by an
aditional dropping resistor. This was commonly something called a
'line cord' which was a piece of 2 core cable with one wire being
resistance wire (!).
I've seen the same thing used for transformerless phonographs, but
the cord was 3-wire, with the resistance wire being used to drop the
filament voltage. You'd see this on "crystal" cartridge phonographs
with a 3-tube setup that included a 50L6, 35Z5 and a 12-volt pre-amp
tube (varied). It was a real puzzle seeing a 2-prong plug ending in
3 leads...
--Chuck
12:49 p.m.
New subject: OT: white LEDs
I've seen the same thing used for transformerless
phonographs, but
the cord was 3-wire, with the resistance wire being used to drop the
filament voltage. You'd see this on "crystal" cartridge phonographs
Yes, tapped line cordes were not uncommon over here either.
with a 3-tube setup that included a 50L6, 35Z5 and a
12-volt pre-amp
tube (varied). It was a real puzzle seeing a 2-prong plug ending in
3 leads...
M\ny of the cheap record palyers over here used a 1 or 2 vavle circuit.
The amplifier valve was something like a UCL82 (triode + output pentode),
the rectifier was either a UY85 or a selenium thing. But the normal way
to get the heater voltage was to tap the winding on the turntable motor,
and use that as an autotransformer.
We ahd some oddities in the radios too. One manufacturer half-wave
rectified the mains to get the HT (B+), os a hot chassis, but used an
autotransformer to run a series string of valves, not a dropping
resistor. Another used a double-wound transformer (and I think a
centre-tapped HT secondatry feeding a full=-wave rectifier), but the
heaters wrre still in series, with a suitable secodnary winding to run
that string. For the transformerless sets (often called 'AC/DC' sets over
here), some manufactuers used a barretter rather than a dropping
resisotr, and at least one set used a normal household light bulb for
that purpose (!).
Philips (IIRC) even made a transformerless valve output stage. 2 output
pentodes (EL84 and UL84, the latter because of the good heater-cathode
insulation IIRC) as a totem pole, with a high impedance speaker (800
ohms) from the centre tape to ground through a capactior. The speaker was
the main problem, it was wound with very thin wire (one reference says
0.3 thou diameter) and it was prone to go open-circuit.
-tony
1:40 p.m.
New subject: OT: white LEDs
On Mon, 1 Mar 2010, Tony Duell wrote:
We ahd some oddities in the radios too. One
manufacturer half-wave
rectified the mains to get the HT (B+), os a hot chassis, but used an
autotransformer to run a series string of valves, not a dropping
resistor. Another used a double-wound transformer (and I think a
centre-tapped HT secondatry feeding a full=-wave rectifier), but the
heaters wrre still in series, with a suitable secodnary winding to run
that string. For the transformerless sets (often called 'AC/DC' sets over
here), some manufactuers used a barretter rather than a dropping
resisotr, and at least one set used a normal household light bulb for
that purpose (!).
In the US, there was the All-American Five design that was used by nearly
all manufacturers for the lower end models. The heaters were wired in
series and the voltage drop added up to 121. That was close enough for
120VAC and thus the transformer could be omitted.
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
2 Mar
2 Mar
1:20 p.m.
New subject: OT: white LEDs
In the US, there was the All-American Five design that
was used by nearly
Sure. IIRC there were several versions with octal, single-ended octal (no
top caps), all-glass miniatures, etc. Wasn't there even a Loctal version?
all manufacturers for the lower end models. The
heaters were wired in
series and the voltage drop added up to 121. That was close enough for
120VAC and thus the transformer could be omitted.
And no dropping resistor either. I seem to remember valves like 12K8
(changer), 12K7 (IF amplifier), 12Q7 (detector/audio amplifier), 50L6
(output) and 35W4 (rectifier).
We did get those sets occasionally in the UK. They were fitted with one
ofd those 'line cord' dropping resistors to allow them to be used on 240V
mains.
-tony
2:52 p.m.
New subject: OT: white LEDs
On 2 Mar 2010 at 21:20, Tony Duell wrote:
Sure. IIRC there were several versions with octal,
single-ended octal
(no top caps), all-glass miniatures, etc. Wasn't there even a Loctal
version?
Yup, the list was there about a week ago.
I liked the novely of the battery-operated portable sets. The
Motorola Pixie was one I was fond of, with its submini tubes. My
first all-transistor radio was actually larger than the Pixie.
--Chuck
3 Mar
3 Mar
10:48 a.m.
New subject: OT: white LEDs
I liked the novely of the battery-operated portable
sets. The
Motorola Pixie was one I was fond of, with its submini tubes. My
first all-transistor radio was actually larger than the Pixie.
So do I. I have a portable radio about the size of a large-ish
transistorised set. But it's valved. And it covers MW (AM broadcast
band), LW _and_ Band 2 FM (FM broadcast band). I think it cheats by
having a couple of germanium diodes in the detector stage, but all the
amplifying stages are valves.
-tony
1 Mar
1 Mar
2:15 p.m.
New subject: OT: white LEDs
On 1 Mar 2010 at 20:49, Tony Duell wrote:
Philips (IIRC) even made a transformerless valve
output stage. 2
output pentodes (EL84 and UL84, the latter because of the good
heater-cathode insulation IIRC) as a totem pole, with a high impedance
speaker (800 ohms) from the centre tape to ground through a capactior.
The speaker was the main problem, it was wound with very thin wire
(one reference says 0.3 thou diameter) and it was prone to go
open-circuit.
There were a few audiophile hobby designs that used multiple
paralleled beam tubes in a cathode-follower arrangement to directly
drive an 8 or 16-ohm speaker. An interesting project for a time
because the WWII-surplus 1625 (7 pin 12.6v version of the 807) could
be had by the caselot for very little. A friend built a grounded-
grid 160m final using them, powering the series filaments directly
from the line. At higher frequencies, it was a common
practice to
hacksaw or drill into the base and fish out the beam-forming
electrodes and bring them to a spare pin for GG operation.
--Chuck
24 Feb
24 Feb
12:30 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Dave McGuire wrote:
On Feb 23, 2010, at 9:14 PM, Brent Hilpert wrote:
I just looked up my old notes and tried it again:
- two LEDs in reverse parallel, or LED and diode
- C = 0.22 uF, 200V
- R ~= 680 to 1K, 1/4W
This targets around 10mA at 120VAC.
~0.2W consumption. Far more efficient than the straight R solution which
consumes around 1.2W, and hence 2W resistor.
Being pedantic, the power company might not like it as it adds reactive
(out-of-phase, power factor) current to the grid. On the other hand, they might
like it as it is capacitive reactance which helps counteract all the inductive
reactance from all those little unloaded wall-warts and transformers people
plug in.
I think I've seen such a circuit used in manufactured equipment too, but I
can't remember what.
I have on occasion run single LEDs from line voltage by paralleling
the LED
with a diode, then putting the pair in series with a C and R. C is
calculated
to provide most of the voltage drop via capacitive reactance, a
small R is
still present to limit inrush current. The diode limits the reverse
voltage and
permits bidirectional current flow so the cap sees AC.
Power consumption and heat dissipation are reduced compared to a
solution using
only R, and a power resistor is not needed.
I haven't tested the circuit over many on/off cycles though, to
find out
whether perhaps the peak in-rush current reduces LED life.
Wow...that's pretty impressive work! Elegant in its simplicity.
7:54 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On 24 Feb 2010 at 0:30, Brent Hilpert wrote:
I think I've seen such a circuit used in
manufactured equipment too,
but I can't remember what.
I believe that most LED "night lights" use a similar scheme.
--Chuck
6:35 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Date: Tue, 23 Feb 2010 18:14:41 -0800
From: hilpert at cs.ubc.ca
To: General at invalid.domain
Subject: Re: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Chuck Guzis wrote:
Hi
The diode across the LED serves two purposes. There is that that you mentioned
about the capacitor and the other is to keep the LED from burning up.
When the voltage reverses on the LED, it is back biased. The LED
zeners at about 10 to 12 volts someplace with almost the same current
as it had when forward biased. A simple I*E calculations shows that
in this mode it is using about 10 time the power as forward biased.
When I first did this I forgot the diode and noticed that the LED
was glowing orange. Checking with my finger confirmed that it was
quite hot.
Dwight
_________________________________________________________________
Hotmail: Powerful Free email with security by Microsoft.
http://clk.atdmt.com/GBL/go/201469230/direct/01/
There's some fellow on the web who's been
making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
I have on occasion run single LEDs from line voltage by paralleling the LED
with a diode, then putting the pair in series with a C and R. C is calculated
to provide most of the voltage drop via capacitive reactance, a small R is
still present to limit inrush current. The diode limits the reverse voltage and
permits bidirectional current flow so the cap sees AC.
Power consumption and heat dissipation are reduced compared to a solution using
only R, and a power resistor is not needed.
I haven't tested the circuit over many on/off cycles though, to find out
whether perhaps the peak in-rush current reduces LED life.
9:17 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
dwight elvey wrote:
(Yes, I mentioned both purposes: AC current flow and limiting the reverse voltage.)
I had a similar experience as you when first experimenting with this with just
a simple R. I wondered about Vr for the LED but didn't find it specified
anywhere in databooks, so I found out what happens as you did. I didn't measure
the breakdown V though, interesting you found it as you specify.
From: hilpert
at cs.ubc.ca
I have on occasion run single LEDs from line voltage by paralleling the LED
with a diode, then putting the pair in series with a C and R. C is calculated
to provide most of the voltage drop via capacitive reactance, a small R is
still present to limit inrush current. The diode limits the reverse voltage and
permits bidirectional current flow so the cap sees AC.
Power consumption and heat dissipation are reduced compared to a solution using
only R, and a power resistor is not needed.
I haven't tested the circuit over many on/off cycles though, to find out
whether perhaps the peak in-rush current reduces LED life.
The diode across the LED serves two purposes. There is that that you mentioned
about the capacitor and the other is to keep the LED from burning up.
When the voltage reverses on the LED, it is back biased. The LED
zeners at about 10 to 12 volts someplace with almost the same current
as it had when forward biased. A simple I*E calculations shows that
in this mode it is using about 10 time the power as forward biased.
When I first did this I forgot the diode and noticed that the LED
was glowing orange. Checking with my finger confirmed that it was
quite hot.
10:01 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
From: hilpert at cs.ubc.ca
---snip---
The diode across the LED serves two purposes. There is that that you mentioned
about the capacitor and the other is to keep the LED from burning up.
When the voltage reverses on the LED, it is back biased. The LED
zeners at about 10 to 12 volts someplace with almost the same current
as it had when forward biased. A simple I*E calculations shows that
in this mode it is using about 10 time the power as forward biased.
When I first did this I forgot the diode and noticed that the LED
was glowing orange. Checking with my finger confirmed that it was
quite hot.
(Yes, I mentioned both purposes: AC current flow and limiting the reverse voltage.)
I had a similar experience as you when first experimenting with this with just
a simple R. I wondered about Vr for the LED but didn't find it specified
anywhere in databooks, so I found out what happens as you did. I didn't measure
the breakdown V though, interesting you found it as you specify.
1:06 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Chuck Guzis wrote:
If you use a 'capacitive dropper' (as they tend to be known in the UK),
it's worth putting a high value resistor (1M or so) in parallel with the
capacitor to discharge it when you unplug the device. Otherwise, if you
unplug it at the right (wrong ?) point on the AC cycle, you'll get zapped
if you touch the plug pins.
-tony
There's some fellow on the web who's been
making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
I have on occasion run single LEDs from line voltage by paralleling the LED
with a diode, then putting the pair in series with a C and R. C is calculated
to provide most of the voltage drop via capacitive reactance, a small R is
still present to limit inrush current. The diode limits the reverse voltage and
permits bidirectional current flow so the cap sees AC.
2:17 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Using capacitive reactance to drop AC line voltage is still alive and
kicking in this design for a PWM controller, where a PIC is run from
line current. At the very least, I'd add a fuse to keep the fire
danger down:
http://tinyurl.com/ygr9vz7
--Chuck
2:23 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On Feb 24, 2010, at 5:17 PM, Chuck Guzis wrote:
Using capacitive reactance to drop AC line voltage is
still alive and
kicking in this design for a PWM controller, where a PIC is run from
line current. At the very least, I'd add a fuse to keep the fire
danger down:
http://tinyurl.com/ygr9vz7
Yes I was quite amused that this article just happened to come
through today :)
-Dave
--
Dave McGuire
Port Charlotte, FL
2:40 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Hi
I was thinking about the capacitor dropper for the LED.
One could add yet another diode and a capacitor that would be
large enough to absorb any inrush if turned on at peak.
You'd put the new diode in series with the LED and
the capacitor in parallel with the LED. The other
back diode would go across both the LED and new diode.
Dwight
From: cclist at sydex.com
To: cctalk at classiccmp.org
Date: Wed, 24 Feb 2010 14:17:19 -0800
Subject: Re: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
Using capacitive reactance to drop AC line voltage is still alive and
kicking in this design for a PWM controller, where a PIC is run from
line current. At the very least, I'd add a fuse to keep the fire
danger down:
http://tinyurl.com/ygr9vz7
--Chuck
_________________________________________________________________
Hotmail: Trusted email with Microsoft?s powerful SPAM protection.
http://clk.atdmt.com/GBL/go/201469226/direct/01/
23 Feb
23 Feb
9:33 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
On Feb 23, 2010, at 8:33 PM, Chuck Guzis wrote:
According to
http://www.muanalysis.com/publications/Quantum-Wells-in-Seasonal-
Department-Christmas-Lights-LED.pdf
the 70-LED strings get by with a resistor only. The 100 LED strings
appear to use a diode. Heaven forfend that a diode bridge be used
for them--that could cost additional cents per string.
There's some fellow on the web who's been making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
There was an article many years ago, in CCI I think, about running
PIC microcontrollers from line voltage through a very large
resistor. Scary stuff.
-Dave
--
Dave McGuire
Port Charlotte, FL
However, to my eye, the biggest abomination are cheap
Christmas tree
LED lights with very pronouced flicker. I haven't researched it,
but I suspect that the LEDs in such strings are hooked in series and
used to self-rectify the line current.
I would hope not. The maximum revers voltage for most LEDs is quite
low.
24 Feb
24 Feb
1:03 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs
the 70-LED strings get by with a resistor only. The
100 LED strings
appear to use a diode. Heaven forfend that a diode bridge be used
for them--that could cost additional cents per string.
Ouch!. When I was designing the white LED stroboscope, I looked at
various LED data sheets on the web. They all emphasised the peak revese
voltage (which was quite low -- a few volts), and said that the LED would
be damaged if this was exceeded. Needless to say putting a resistor in
series and applying 110V AC is going to exceed that revese voltage.
There's some fellow on the web who's been making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
The normal trick is to put a diode in inverse parallel. The diode only
needs to have a PIV equal to the _forward_ voltage of the LED (think
about it, either the diode of LED is forward biased on each half cycle),
so just aobut any diode would do. I'd probably use a 1N4007 since it
would survive if the LED went open-circut, and anyway, I have them in
stock :-)
-tony
22 Feb
22 Feb
7 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On Feb 22, 2010, at 4:35 PM, Alexander Schreiber wrote:
What works in favour of the white LEDs is that everybody has been
working _real_ hard to get their output _way_ up. For the other
colors,
the pressure for more light isn't that intense.
They're working just as hard for IR (in the form of laser diodes),
and making great strides there as well.
-Dave
--
Dave McGuire
Port Charlotte, FL
White LEDs have become one of the most efficient light
sources.
Is that really true? I would have suspected that red LEDs would be
far more efficient in terms of lumens-per-watt. The drawback being
that they're monochromatic.
9:44 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
Which are more efficient (without regard to luminous intensity)--LEDs
or EL lamps? I remember an article during the 1960s in Popular
Science about how someday, the walls of our rooms would be EL panels.
I still have a few EL nightlights scattered around the house.
--Chuck
23 Feb
23 Feb
6:11 a.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
From: cclist at sydex.com
To: cctalk at classiccmp.org
Date: Mon, 22 Feb 2010 21:44:06 -0800
Subject: Re: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
Which are more efficient (without regard to luminous intensity)--LEDs
or EL lamps? I remember an article during the 1960s in Popular
Science about how someday, the walls of our rooms would be EL panels.
I still have a few EL nightlights scattered around the house.
--Chuck
Hi
My wife was always complaining about leaving lights on and
such so when I got two EL night lights for the bathroom,
it took a while to convince her that it would be OK to
leave them on all the time.
I forgot exactly what it figured out to but it was less then
a dollar to run both of them for a year. That convinced her
to just leave them in, all the time.
Dwight
_________________________________________________________________
Hotmail: Trusted email with Microsoft?s powerful SPAM protection.
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22 Feb
22 Feb
2:01 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On Mon, 22 Feb 2010 11:47:10 -0800
"Chuck Guzis" <cclist at sydex.com> wrote:
Well. I meant LED in general, white
in special, in contrast to e.g.
CFL, HID, sulfur, ... Also take in account that the human eye has a
fairly low sensitivity for red light. Lumens are weightend by the
spectral sesitivity of the human eye.
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
White LEDs
have become one of the most efficient light sources.
Is that really true? I would
have suspected that red LEDs would be
far more efficient in terms of lumens-per-watt.
2:29 p.m.
New subject: OT: white LEDs (was: Re: Solderless breadboarding (and 68010 vs 68000))
On 22 Feb 2010 at 23:01, Jochen Kunz wrote:
Well. I meant LED in general, white in special, in
contrast to e.g.
CFL, HID, sulfur, ... Also take in account that the human eye has a
fairly low sensitivity for red light. Lumens are weightend by the
spectral sesitivity of the human eye. -
LED street lights are beginning to appear on some California streets.
As I understand it, there is less light output in absolute terms, but
the overall effect is one of providing more useful illumination than
the traditional high-pressure sodium lamps. See:
http://cbs5.com/video/?id=48013 at kpix.dayport.com
for a video report.
At amazon.com, you can even purchase a 100 watt LED luminaire for
US$720.
http://www.amazon.com/Energy-Saving-Street-Meters-
Illuminated/dp/B000QY0L54
In my lifetime, I've seen street lighting move from incandescent to
mercury vapor (horrible light quality) to low-pressure sodium
(yellow) to high-pressure sodium. LEDs look like a winner and may
well reduce some of the night-sky "light pollution".
--Chuck
2:56 p.m.
New subject: OT: white LEDs
Nice!!! Definitely should see those nationwide, its ashame they
cost so much which I mean - they are LED's, they are a couple of cents
each, its this all profit gouging on Green Products???
Curt
Chuck Guzis wrote:
On 22 Feb 2010 at 23:01, Jochen Kunz wrote:
Well. I meant LED in general, white in special,
in contrast to e.g.
CFL, HID, sulfur, ... Also take in account that the human eye has a
fairly low sensitivity for red light. Lumens are weightend by the
spectral sesitivity of the human eye. -
LED street lights are beginning to appear on some California streets.
As I understand it, there is less light output in absolute terms, but
the overall effect is one of providing more useful illumination than
the traditional high-pressure sodium lamps. See:
http://cbs5.com/video/?id=48013 at kpix.dayport.com
for a video report.
At amazon.com, you can even purchase a 100 watt LED luminaire for
US$720.
http://www.amazon.com/Energy-Saving-Street-Meters-
Illuminated/dp/B000QY0L54
In my lifetime, I've seen street lighting move from incandescent to
mercury vapor (horrible light quality) to low-pressure sodium
(yellow) to high-pressure sodium. LEDs look like a winner and may
well reduce some of the night-sky "light pollution".
--Chuck
4:40 p.m.
New subject: OT: white LEDs
On Mon, Feb 22, 2010 at 05:56:43PM -0500, Curt @ Atari Museum wrote:
Nice!!! Definitely should see those nationwide,
its ashame they
cost so much which I mean - they are LED's, they are a couple of cents
each, its this all profit gouging on Green Products???
A couple of cents? Yeah, for the small low power (<< 1 W) ones you use
for indicators in electronics or christmas tree lights. The high power
stuff is still rather pricey. While I've no doubt that the manufacturers
are milking every cent of profit they can, those _aren't_ that cheap or
easy to produce, otherwise every semiconductor fablet in china would
make them by the barrel.
Also, make no mistake, the "green" aspect takes a second (or third) seat
to more important aspects when deploying LED for things like traffic
signs and such. Especially for traffic sings, while the LED versions
most likely are significantly more expensive than incandescents, they
are big money savers in maintenance (getting someone up with a ladder to
change bulbs every once in a while ain't that cheap, especially in
places like Switzerland where there _is_ no dirt cheap labor) and
operating costs (power bills). The reduced power consumption of course
lends itself to being toutet as "greener" ;-)
Regards,
Alex.
--
"Opportunity is missed by most people because it is dressed in overalls and
looks like work." -- Thomas A. Edison
5:07 p.m.
New subject: OT: white LEDs
Here in the heart of the frozen midwest, where traffic signals have been
mass changed to LEDs, we have another problem. In the past, snow and ice
didn't accumulate in the traffic signal light housings stuck to the lens
unless there was a lot of wind in the right direction. Even then, the
signals were incandescent bulbs and kept it melted off.
Now with LEDs, that doesn't happen, and more wintertime maintenance is
required. Though it's still not as much as all the bulb-changing that used
to be necessary.
At 01:40 AM 2/23/2010 +0100, you wrote:
On Mon, Feb 22, 2010 at 05:56:43PM -0500, Curt @ Atari
Museum wrote:
-----
17. [Computing] At Group L, Stoffel oversees six first-rate programmers, a
managerial challenge roughly comparable to herding cats. --The Washington
Post Magazine, June 9, 1985
--... ...-- -.. . -. ----. --.- --.- -...
tpeters at nospam.mixcom.com (remove "nospam") N9QQB (amateur radio)
"HEY YOU" (loud shouting) WEB: http://www.mixcom.com/tpeters
43? 7' 17.2" N by 88? 6' 28.9" W, Elevation 815', Grid Square
EN53wc
WAN/LAN/Telcom Analyst, Tech Writer, MCP, CCNA, Registered Linux User 385531
Nice!!! Definitely should see those
nationwide, its ashame they
cost so much which I mean - they are LED's, they are a couple of cents
each, its this all profit gouging on Green Products???
A couple of cents? Yeah, for the small low power (<< 1 W) ones you use
for indicators in electronics or christmas tree lights. The high power
stuff is still rather pricey. While I've no doubt that the manufacturers
are milking every cent of profit they can, those _aren't_ that cheap or
easy to produce, otherwise every semiconductor fablet in china would
make them by the barrel.
Also, make no mistake, the "green" aspect takes a second (or third) seat
to more important aspects when deploying LED for things like traffic
signs and such. Especially for traffic sings, while the LED versions
most likely are significantly more expensive than incandescents, they
are big money savers in maintenance (getting someone up with a ladder to
change bulbs every once in a while ain't that cheap, especially in
places like Switzerland where there _is_ no dirt cheap labor) and
operating costs (power bills). The reduced power consumption of course
lends itself to being toutet as "greener" ;-)
Regards,
Alex.
--
"Opportunity is missed by most people because it is dressed in overalls and
looks like work." -- Thomas A. Edison
5:49 p.m.
New subject: OT: white LEDs
That is true, they last longer and would save a heck of a lot of
maintenance... I always thought like 10-15 years ago "when will they
make traffic lights and street lights smart enough that when they fail,
a signal is sent so that someone will come and fix them..." Today its
usually when a traffic signal breaks and someone calls on their cell to
9-1-1 that there is a potential safety hazard, I would assume the
electric co. drives around making inspections looking for dead street
lights. I would think that with their new low power lights there
would then come the eventual Wifi status transmitter that would send out
a functional status of a light, traffic signal, etc that could all come
into a center monitoring station and know when something fails.
I was incorrect on the LED's as you pointed out, the more industrial
type LED's are far more expensive.
Curt
Alexander Schreiber wrote:
On Mon, Feb 22, 2010 at 05:56:43PM -0500, Curt @ Atari
Museum wrote:
Nice!!! Definitely should see those
nationwide, its ashame they
cost so much which I mean - they are LED's, they are a couple of cents
each, its this all profit gouging on Green Products???
A couple of cents? Yeah, for the small low power (<< 1 W) ones you use
for indicators in electronics or christmas tree lights. The high power
stuff is still rather pricey. While I've no doubt that the manufacturers
are milking every cent of profit they can, those _aren't_ that cheap or
easy to produce, otherwise every semiconductor fablet in china would
make them by the barrel.
Also, make no mistake, the "green" aspect takes a second (or third) seat
to more important aspects when deploying LED for things like traffic
signs and such. Especially for traffic sings, while the LED versions
most likely are significantly more expensive than incandescents, they
are big money savers in maintenance (getting someone up with a ladder to
change bulbs every once in a while ain't that cheap, especially in
places like Switzerland where there _is_ no dirt cheap labor) and
operating costs (power bills). The reduced power consumption of course
lends itself to being toutet as "greener" ;-)
Regards,
Alex.
7:20 p.m.
New subject: OT: white LEDs
I think Luxeon still has the high mark in the industrial high power LED market. When
these first came out, 6 years ago they were truly amazing, 1 amp LEDs! Integral thermal
pad on the back for heatsinking. In the dark, you could hold a 35mm slide in front of
one, 6" away and get a sharp bright image in the wall, as its almost a point source.
If you look at one in the microscope, it looks like an LED with some sort of phosphor
painted over the semiconductor. Is that how these things work, its really a high
efficency IR LED, with a phosphor doubler to bring the wavelength into visible? Just
speculating...
I was using them in a ring light for a downhole well camera. Not that expensive, about $6
each.
Randy
Date: Mon, 22 Feb 2010 20:49:47 -0500
From: curt at atarimuseum.com
To:
Subject: Re: OT: white LEDs
That is true, they last longer and would save a heck of a lot of
maintenance... I always thought like 10-15 years ago "when will they
make traffic lights and street lights smart enough that when they fail,
a signal is sent so that someone will come and fix them..." Today its
usually when a traffic signal breaks and someone calls on their cell to
9-1-1 that there is a potential safety hazard, I would assume the
electric co. drives around making inspections looking for dead street
lights. I would think that with their new low power lights there
would then come the eventual Wifi status transmitter that would send out
a functional status of a light, traffic signal, etc that could all come
into a center monitoring station and know when something fails.
I was incorrect on the LED's as you pointed out, the more industrial
type LED's are far more expensive.
Curt
Alexander Schreiber wrote:
> On Mon, Feb 22, 2010 at 05:56:43PM -0500, Curt @ Atari Museum wrote:
>
>> Nice!!! Definitely should see those nationwide, its ashame they
>> cost so much which I mean - they are LED's, they are a couple of cents
>> each, its this all profit gouging on Green Products???
>>
>
> A couple of cents? Yeah, for the small low power (<< 1 W) ones you use
> for indicators in electronics or christmas tree lights. The high power
> stuff is still rather pricey. While I've no doubt that the manufacturers
> are milking every cent of profit they can, those _aren't_ that cheap or
> easy to produce, otherwise every semiconductor fablet in china would
> make them by the barrel.
>
> Also, make no mistake, the "green" aspect takes a second (or third) seat
> to more important aspects when deploying LED for things like traffic
> signs and such. Especially for traffic sings, while the LED versions
> most likely are significantly more expensive than incandescents, they
> are big money savers in maintenance (getting someone up with a ladder to
> change bulbs every once in a while ain't that cheap, especially in
> places like Switzerland where there _is_ no dirt cheap labor) and
> operating costs (power bills). The reduced power consumption of course
> lends itself to being toutet as "greener" ;-)
>
> Regards,
> Alex.
>
_________________________________________________________________
Hotmail: Free, trusted and rich email service.
http://clk.atdmt.com/GBL/go/196390708/direct/01/
7:25 p.m.
New subject: OT: white LEDs
On Feb 22, 2010, at 10:20 PM, Randy Dawson wrote:
If you look at one in the microscope, it looks like an
LED with
some sort of phosphor painted over the semiconductor. Is that how
these things work, its really a high efficency IR LED, with a
phosphor doubler to bring the wavelength into visible? Just
speculating...
No, they're coated with a blend of phosphors designed to give
"sorta" white light. The native LED underneath the phosphor coating
is usually blue.
Remember, if you double the narrow-band output of some common IR
LED output, you'll get some narrow-band visible output...more or less
a single visible color.
-Dave
--
Dave McGuire
Port Charlotte, FL
23 Feb
23 Feb
11:34 a.m.
New subject: OT: white LEDs
If you look at one in the microscope=2C it looks like
an LED with some sort=
of phosphor painted over the semiconductor. Is that how these things work=
=2C its really a high efficency IR LED=2C with a phosphor doubler to bring =
the wavelength into visible? Just speculating...
Most, if nto all white LEDs are actually a blue LED device coupled with a
yellow phosphor. If you shine UV light sourve on one, it will glow yellow
due to the phosphor. UV LEDs work well for this (yes, said pound shop had
some UV LED torches (flashlights) at 2 for a pound, designed to be used
to show up the fluorescent markings on banknotes to detect forgeries. I
added one to my toolkit, it's very useful for detecting flourescent
markings on all sorts of otehr things, for checking the colour of
phosphor in display panels, and the like).
I was using them in a ring light for a downhole well camera. Not that expe=
nsive=2C about $6 each.
Has anyone ever tried them for flim photograhpy? THe data sheets I looked
at showed a fairly continuous output spectrrum (unlike the pure colour
LEDs, of course), which could presumably be filtered into something that
looked like daylight to colour film.
-tony
1:08 p.m.
New subject: OT: white LEDs
On Tue, 23 Feb 2010 19:34:49 +0000 (GMT)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
Has anyone ever tried them for flim photograhpy?
I saw white LEDs used as lighting for macro photography. Though with
digital cameras. Most white LEDs are weak on the red side of the
spectrum. Sometimes this gets mitigated by adding extra red LEDs.
Cree uses this trick to get a CRI of 90 and more in its LED moduls.
Check the CRI rating in the data sheet. (E.g. the Cree XP-G cool
white is at 75.)
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
24 Feb
24 Feb
12:40 p.m.
New subject: OT: white LEDs
Has anyone
ever tried them for flim photograhpy?
I saw white LEDs used as lighting for macro
photography. Though with digital cameras. Most white LEDs are weak on the red
side of the
spectrum. Sometimes this gets mitigated by adding extra red LEDs.
I would have thought the problem with doing that is that the red LED
output is a very narrow band of wavelengths. It may not compensate that
well on colour film
I guess the thing to do is to try it. OK, sometime when I've got some
spare time I will pay around with various LEDs, a camera and a grey card.
-tony
2:52 p.m.
New subject: OT: white LEDs
On 24/02/2010 20:40, Tony Duell wrote:
Yes, that's what I was thinking of using them for. A ring of white LEDs
around the lens may be useable as a cheap alternative to a ringdlash
(which I don't own, and can't justify buying).
You can actually buy ringlights made in that manner, and they work
pretty well. There are usually some cheap ones on a famous "auction"
site and more expensive ones available from photographic suppliers.
I've seen DIY versions on sites such as
http://www.diyphotography.net/search/node/ringlight
White LEDs are also popular with some microscopists, and I have a rather
Heath Robinson device I use in that way. I keep meaning to rebuild it
properly rather than using crocodile clip to hold parts in place, but it
gives good controllable light. At least one of the microscopy sites has
some reviews suggesting makes/types that have a good spectrum:
http://www.micrographia.com/index.htm
http://www.micrographia.com/articlz/artmicgr/lmpideal/lmpi0500.htm
--
Pete Peter Turnbull
Network Manager
University of York
Has anyone ever tried them for flim photograhpy?
I saw white LEDs used as lighting for macro photography. Though with 
3:37 p.m.
New subject: OT: white LEDs
-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Pete Turnbull
Sent: Wednesday, February 24, 2010 2:52 PM
To: On-Topic and Off-Topic Posts
Subject: Re: OT: white LEDs
[snip]
White LEDs are also popular with some microscopists,
and I have a
rather
Heath Robinson device I use in that way. I keep meaning to rebuild it
properly rather than using crocodile clip to hold parts in place, but
it
gives good controllable light. At least one of the microscopy sites
has
some reviews suggesting makes/types that have a good spectrum:
http://www.micrographia.com/index.htm
http://www.micrographia.com/articlz/artmicgr/lmpideal/lmpi0500.htm
--
My daughter wanted a microscope for Christmas (!) and 'Santa brought' what seems
to be a really nice unit available at Top Ten Toys. I mention it because it apparently
uses white LEDs for both above- and below-stage lighting (switch selectable) and the view
is great. It's WAY better than the microscope I had as a kid. -- Ian
10:25 p.m.
New subject: OT: white LEDs
You can actually buy ringlights made in that manner,
and they work
pretty well. There are usually some cheap ones on a famous "auction"
It is my experience that just about anything intended for photograp[hic
use is way overpriced :-=). OK, I can't grind lenses, so I am happy to
pay for good ones, but I am not going to pay high prices for things I can
make in an afternoon or so. Quite apart from the fact that making the
device and experiemnting with it is more fun to me than taking photographs...
-tony
26 Feb
26 Feb
11:54 a.m.
New subject: OT: white LEDs
Tony Duell [ard at p850ug1.demon.co.uk] wrote:
OK, I know how to grind lenses and mirrors by hand (using onepiece of
glass against aonther with suitable abrasives between them, and the fact
that by doing this all you cna produce is spherical surfaces (which are
not the right surfaces for lenes, but until quite recently, it's all that
could be accurately made). But as you and I well know, to grind a lens
take a lot of practice.
Since I can't get the optical glasses easily anyway, I find it more
sensible to buy second-hand lens assemblies. For the sort of cameras I
have, the faults in them are likely to be mechancial, mostly gummmed up
grease. I am capable of dismantlig diaphragm or a focussing mount and
cleaning/rebuilding it). Lens griding would be an intereting thing to
try, sure, but there are only 86400 seconds in a day...
This does not contradict my earlier comments that IMHO people who want to
do electronics as a hobby, or restore classic computers, should learn to
solder. Notice I haven't said that everybody should learn to solder.
There are plenty of people who persue other interests for which soldering
is not necessary.
-tony
OK, I can't grind lenses,
Oh please! Herschel managed in the late 1700s so I don't see what
possible excuse you can have :-) 
23 Feb
23 Feb
1:15 p.m.
New subject: OT: white LEDs
Has anyone ever tried them for flim photograhpy? THe
data sheets I looked
at showed a fairly continuous output spectrrum (unlike the pure colour
LEDs, of course), which could presumably be filtered into something that
looked like daylight to colour film.
I have used a white LED to paint light in both digital and film
photography successfully.
I am using a blue white Photon Micro light to light macro photographic
subjects in the field at night. I use a tripod to hold the camera
still for a time exposure and light the item by moving the LED
microlight all around. nice color, no shadows. Exposures run from a
few seconds to about 60 seconds.
I have been meaning to get several friends together and have them wave
their micro lights in a group picture but have not done it yet,
probably this summer.
To keep it on topic this technique would be good to take shadowless
photos of older electronic components and boards.
Paxton
Astoria, Oregon
USA
--
Paxton Hoag
Astoria, OR
USA
1:48 p.m.
New subject: OT: white LEDs
On Feb 23, 2010, at 4:15 PM, Paxton Hoag wrote:
I am using a blue white Photon Micro light to light
macro photographic
subjects in the field at night. I use a tripod to hold the camera
still for a time exposure and light the item by moving the LED
microlight all around. nice color, no shadows. Exposures run from a
few seconds to about 60 seconds.
I have been meaning to get several friends together and have them wave
their micro lights in a group picture but have not done it yet,
probably this summer.
Photon lights are fantastic. I keep one in my pocket every day.
I'd be lost without it!
-Dave
--
Dave McGuire
Port Charlotte, FL
1:29 p.m.
New subject: OT: white LEDs
Tony Duell wrote:
Has anyone ever tried them for flim[sic]
photograhpy[sic]? THe data sheets I looked
at showed a fairly continuous output spectrrum[sic] (unlike the pure colour
LEDs, of course), which could presumably be filtered into something that
looked like daylight to colour film.
As long as the output color temperature of the light is fairly
consistent, it doesn't matter much if it skewed to one side or another.
We shoot gray cards to achieve a neutral white balance.
When you deal with mixed lighting scenarios inside a house, you're
basically dealing w/ the same thing. You might have some filtered
daylight through a window, some incandescent bulbs, and so on.
Keith
24 Feb
24 Feb
12:45 p.m.
New subject: OT: white LEDs
Tony Duell wrote:
Well, it pmatters on reversal film, in that you can't correct it later.
But of course you can use colour correction filters when you take the
photograph.
But only if the light spectrum is relatively continuous. No way can you
correct the ligth from a low-pressure sodium lamp, or LEDs other than
white ones.
Has anyone ever tried them for flim[sic]
photograhpy[sic]? THe data sheets I looked
at showed a fairly continuous output spectrrum[sic] (unlike the pure colour
LEDs, of course), which could presumably be filtered into something that
looked like daylight to colour film.
As long as the output color temperature of the light is fairly
consistent, it doesn't matter much if it skewed to one side or another.
We shoot gray cards to achieve a neutral white balance.
When you deal with mixed lighting scenarios inside a house, you're
basically dealing w/ the same thing. You might have some filtered
daylight through a window, some incandescent bulbs, and so on.
When you have mixed lighting, it's imppossible to get the colours spot-on
(unless you filter the light sources). Whether that matters depends on
what you are photographing and why.
My idea for usiong white LEDs is a shadowless light source for macro
work, which in my case is likely to be bits of computers, calculators,
etc. The colours don't have to be perfect (I am not going to try to
match them later), but of course I don't want a strong overall cast to
the picture.
-tony
26 Feb
26 Feb
10:07 a.m.
New subject: OT: white LEDs
Tony Duell wrote:
I use an array of white LEDs behind a polarizing filter in combination
with a second polarizer on my lens to minimize reflections from glossy
surfaces.
Peace... Sridhar
I was using
them in a ring light for a downhole well camera. Not that expe=
nsive=2C about $6 each.
Has anyone ever tried them for flim photograhpy? THe data sheets I looked
at showed a fairly continuous output spectrrum (unlike the pure colour
LEDs, of course), which could presumably be filtered into something that
looked like daylight to colour film.
22 Feb
22 Feb
8:17 p.m.
New subject: OT: white LEDs
Curt @ Atari Museum wrote:
That is true, they last longer and would save a heck
of a lot of
maintenance
Right. Instead of a single bulb, there are many smaller LEDs, and the
biggest benefit is that they all don't fail at the same time. This
makes them much safer. I don't know what the MTBF is on those things
but I've seen a couple burned out in some of the lights around here.
... I always thought like 10-15 years ago "when
will they
make traffic lights and street lights smart enough that when they fail,
a signal is sent so that someone will come and fix them..."
I used to talk to the technical people in charge of these types of
projects in city/county/etc government. This isn't all that new,
either. They've used RS422 and RS485 and run copper twisted pair
between the lights, and then home run single mode fiber back to the
centralized building.
I got involved w/ them because they wanted to "network"-ify these old
light controllers. The newer controllers are ethernet-based. I gave
them a solution to transmit serial over tcp/ip, and then use small
network switches that would use the legacy single mode. The advantage
there was that they'd now have ethernet in these street-side boxes which
made things like network-based cameras easy to connect.
These switches had two single mode fiber ports (or multimode for shorter
distances) and then around 6-8 copper 10/100 ports. What made them
great for these types of projects is that they were industrial
temperature rated. They were -50C to +100C rated, and designed for long
term use at -40C to +75C.
At the central location, they had big monitoring screens where they
could see the status of every light, and have live video of the
intersections. Pretty neat.
I would think that with their new low power lights
there
would then come the eventual Wifi status transmitter that would send out
a functional status of a light, traffic signal, etc that could all come
into a center monitoring station and know when something fails.
Yup. I designed some of these types of networks too! Especially nice
when they already have some of municipality wide wifi installed.
Keith
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