6 Jun
2009
6 Jun
'09
5:45 p.m.
To cut a long story short, we have put a 240v/50Hz motor from an IBM
56 verifier in the keypunch and that part works great. We transplanted
the motor cradle and motor start relay too. The manual showed how the
DC power supply could be configured for 115v or 208v or 240v, though
all at 60Hz. Well we tried that and the DC produced was about 41volts
instead of 48v, which was more or less what was predicted by
collective list wisdom. The relay logic intermittently seems to work.
The existing capacitor in the ferro-resonant power supply is marked
15MF (incidentally, how come MF does not mean Mega Farad), and rated
at 330VAC. I think this means ideally I need (90/50)^2 * 15 which is
21.6MF. I have ordered two more capacitors to connect in parallel, one
5uF and one 1.5uF, to give 21.5 total, both at 440VAC.
There was one wire hanging off the bottom of the mechanism which we
have reconnected. The mechanical side gradually came back to life,
probably the grease had gone hard at the surface or oil needed
spreading about a bit. It now fairly reliably moves cards from the
input hopper to the output stacker. There were chads stuck all over
the place and at first, the top row did not poke the chads out of the
holes and we joked about hanging chads and George Bush coming back.
Comparing my old keypunch and this one, there is an auger screw in the
old one but not in this, but after looking through the parts list, it
seems IBM deleted that part. Anyway a 9mm twist drill pushed up the
empty auger hole and twisted and wiggled and a backlog of old chads
and strangely black cloth came out and now it punches cleanly, or at
least it does when the relay logic feels like it. It even prints the
codes. To get alpha I had to hold down the alpha key, though I think
it should latch in logic, probably the low DC supply again.
The whole thing looks like it has been re-sprayed in the right colour/
texture of paint and thoroughly cleaned. Maybe a factory refurbished
unit.
Picture of it with cards in the track here, covers off:
http://www.ict1301.co.uk/emulator/029_03_09
I hope to be using it soon to correct any cards which wreck when I try
to read in the library of ICT 1301 software so I can capture it on my
Mac, from where I can load it via RS232 into my 1301 as well as make
it available to others.
Roger Holmes
6 Jun
6 Jun
6:01 p.m.
On 6 Jun 2009 at 22:45, Roger Holmes wrote:
Anyway a 9mm twist drill pushed up the
empty auger hole and twisted and wiggled and a backlog of old chads
and strangely black cloth came out and now it punches cleanly, or at
least it does when the relay logic feels like it.
Sounds great, Roger. That black cloth may just be old shredded
ribbon from the print mechanism.
I think MAI here in the US used to buy up old IBM card gear, refurb,
then lease it out again.
--CHuck
6:51 p.m.
Roger Holmes wrote:
To cut a long story short, we have put a 240v/50Hz motor from an IBM
56 verifier in the keypunch and that part works great. We transplanted
the motor cradle and motor start relay too. The manual showed how the
DC power supply could be configured for 115v or 208v or 240v, though
all at 60Hz. Well we tried that and the DC produced was about 41volts
instead of 48v, which was more or less what was predicted by
collective list wisdom. The relay logic intermittently seems to work.
The existing capacitor in the ferro-resonant power supply is marked
15MF (incidentally, how come MF does not mean Mega Farad), and rated
at 330VAC. I think this means ideally I need (90/50)^2 * 15 which is
21.6MF. I have ordered two more capacitors to connect in parallel, one
5uF and one 1.5uF, to give 21.5 total, both at 440VAC.
It will be interesting to hear how the additional caps work out, both as to
how it works out for the ferro-resonant power supply and whether the
proper voltage improves the relay circuitry behaviour.
IIRC, the IBM relay practices document someone pointed to earlier in the
discussion made some mention of a large variation tolerance, but it may have
meant the system tolerance was fairly narrow so as to accept a wide variation
amongst individual relays, rather than implying a large tolerance on system parameters.
In my own hacking/design experience with semi-complex relay circuitry I did
find them more sensitive to voltage levels than initially expected, when trying
to get optimum performance. There were some conflicting characteristics
involving voltage and the stored energy in the relay solenoid vs clock speed
and system design that resulted in the power supply requirements being tighter
than expected.
10 Jun
10 Jun
7:05 p.m.
Eric Smith wrote:
Nico de Jong wrote:
Erm... I doubt this. I saw a 2 farad cap at a surplus place in Lima,
Ohio. It was rated at 12 volts, and looked like a sawed-off oil drum.
I think there's some sort of square-cube thing going on here that makes
ever-increasing values of capacitance ever huger.
Warren
I wonder how many Farads a car battery helds Nico
If you empty it out and fill it with capacitors, it will hold a few
megafarads at 2 volts. 
7:11 p.m.
On Wed, 2009-06-10 at 13:05 -1000, Warren Wolfe wrote:
Eric Smith wrote:
You can buy 10F 15V capacitors in car audio shops. They're about the
size of a beer can (a normal UK/EU 500ml can, not a dinky little US
330ml can).
Gordon
Nico de Jong wrote:
Erm... I doubt this. I saw a 2 farad cap at a surplus place in Lima,
Ohio. It was rated at 12 volts, and looked like a sawed-off oil drum.
I think there's some sort of square-cube thing going on here that makes
ever-increasing values of capacitance ever huger. I wonder how many Farads a car battery helds Nico
If you empty it out and fill it with capacitors, it will hold a few
megafarads at 2 volts.
11 Jun
11 Jun
7:10 p.m.
Gordon JC Pearce wrote:
You can buy 10F 15V capacitors in car audio shops.
They're about the
size of a beer can (a normal UK/EU 500ml can, not a dinky little US
330ml can).
Thanks, Gordon, for pointing out that my computer knowledge is not the
only knowledge I have that is outdated. *SIGH* I haven't gone
"electronics exploring" in many years...
Warren
10 Jun
10 Jun
7:16 p.m.
On Jun 10, 2009, at 7:05 PM, Warren Wolfe wrote:
Erm... I doubt this. I saw a 2 farad cap at a surplus place in
Lima, Ohio. It was rated at 12 volts, and looked like a sawed-off
oil drum. I think there's some sort of square-cube thing going on
here that makes ever-increasing values of capacitance ever huger.
Urr? I've got a bag of 0.5F 5.5V capacitors in my parts stocks.
They're about 0.5" in diameter and 0.25" tall. Times have changed.
-Dave
--
Dave McGuire
Port Charlotte, FL
I wonder how many Farads a car battery helds Nico
If you empty it out and fill it with capacitors, it will hold a
few megafarads at 2 volts.
11 Jun
11 Jun
7:11 p.m.
Dave McGuire wrote:
On Jun 10, 2009, at 7:05 PM, Warren Wolfe wrote:
Erm... I doubt this. I saw a 2 farad cap at a surplus place in
Lima, Ohio. It was rated at 12 volts, and looked like a sawed-off
oil drum. I think there's some sort of square-cube thing going on
here that makes ever-increasing values of capacitance ever huger.
Urr? I've got a bag of 0.5F 5.5V capacitors in my parts stocks.
They're about 0.5" in diameter and 0.25" tall. Times have changed.
Yeah, you, too. Get off my lawn. <Grin>
Warren
I wonder how many Farads a car battery helds Nico
If you empty it out and fill it with capacitors, it will hold a few
megafarads at 2 volts. 
10 Jun
10 Jun
8:45 p.m.
Warren Wolfe wrote:
Erm... I doubt this. I saw a 2 farad cap at a
surplus place in Lima,
Ohio. It was rated at 12 volts, and looked like a sawed-off oil drum.
That's
much older technology. As others here have observed, you can now
get a 100F capacitor that is quite compact, though they have voltage
ratings between 2V and 2.7V.
I think there's some sort of square-cube thing
going on here that
makes ever-increasing values of capacitance ever huger.
Not really. For a given
technology, the volume is roughly linearly
related to the product of the capacitance and voltage.
10:44 p.m.
New subject: large capacitors [was: IBM 029 progress]
Eric Smith wrote:
Warren Wolfe wrote:
Erm... I doubt this. I saw a 2 farad cap at a
surplus place in Lima,
Ohio. It was rated at 12 volts, and looked like a sawed-off oil drum.
That's
much older technology. As others here have observed, you can now
get a 100F capacitor that is quite compact, though they have voltage
ratings between 2V and 2.7V.
> I think there's some sort of square-cube thing going on here that
> makes ever-increasing values of capacitance ever huger. Not really. For a given technology, the volume is
roughly linearly
related to the product of the capacitance and voltage.
That doesn't make sense. energy = 1/2 * C * V^2. You are saying if you
double the size of the cap you can handle double the voltage, but that
means four times the energy. That isn't right. It is the stored energy
that is linear with the size of the cap (roughly).
I agree that you can double the capacitance if you double the volume,
which means doubling the stored energy. Great. This is demonstrated by
wiring two "x" farad caps in parallel.
But if you wire them in series so they can handle twice the voltage, the
capacitance is also cut in half. E = 1/2 * (1/2 C) * (2V)^2, which
works out to double the 1/2*C*V^2.
11 Jun
11 Jun
5:10 a.m.
New subject: large capacitors [was: IBM 029 progress]
Warren Wolfe wrote:
I think there's some sort of square-cube thing
going on here that
makes ever-increasing values of capacitance ever huger.
I wrote:
Not really. For a given technology, the volume is
roughly linearly
related to the product of the capacitance and voltage.
Jim Battle wrote:
That doesn't make sense. energy = 1/2 * C * V^2.
You are saying if
you double the size of the cap you can handle double the voltage, but
that means four times the energy. That isn't right. It is the stored
energy that is linear with the size of the cap (roughly).
You're right. I
should have said that for a given technology and rated
voltage, the volume is roughly linearly related to the capacitance. No
square or cube there.
Eric
9:57 a.m.
New subject: large capacitors [was: IBM 029 progress]
On Wed, 10 Jun 2009 21:44:07 -0500, Jim Battle wrote:
> Not really. For a given technology, the volume is
roughly linearly
> related to the product of the capacitance and voltage.
That doesn't make sense. energy = 1/2 * C * V^2.
You are saying if you
double the size of the cap you can handle double the voltage, but that
means four times the energy. That isn't right. It is the stored energy
that is linear with the size of the cap (roughly).
I agree that you can double the capacitance if you
double the volume,
which means doubling the stored energy. Great. This is demonstrated by
wiring two "x" farad caps in parallel.
But if you wire them in series so they can handle twice
the voltage, the
capacitance is also cut in half. E = 1/2 * (1/2 C) * (2V)^2, which
works out to double the 1/2*C*V^2.
Peek working voltage is determined by the strength of the dielectric not the surface area
of the plates.
The thinner the dialetic (insolator) the greater the Capacitance with a resulting lowering
of the max working
voltage given the reduced insilation.
The other factor for determing the the working voltage is the amount of heat generated
from leakage due to
internal resistance, which is also directly related to the insulator used ans its
thickness. The leakage
current for a given dielectric goes up with the voltage. I=E/R Tells us given a fixed
leakage as the voltage
goes up so does the current, so if both the I and the E both go up then the power (watts
to be dissipated)
has noware to go but in the form of heat. Often with a big bang if the overvoltage or the
breakdown of the
dialetic are extream.
Using activated carbon or better yet nano tubes as plates and an unspecified molecularily
thin super
insolator, we double-layer supercapacitors measured in Farads the size of your thumb.
The semiconductor industery showed us how by making the insolation layer very, very thin
we could bulid
on chip capacitors with microscopic plate areas.
So given the previous examples in this thread are we talking, waxpaper and aluminum foil,
silver plated
mica, oil filed, or super-capacitors ?
The other Bob
7:15 p.m.
Eric Smith wrote:
Hmmm... Okay. I'll take your word on this. Thanks for the info.
Warren
Warren Wolfe wrote:
Gee, I feel so.... no longer supported.
Erm... I doubt this. I saw a 2 farad cap at a
surplus place in
Lima, Ohio. It was rated at 12 volts, and looked like a sawed-off
oil drum.
That's much older technology. As others here have observed, you can
now get a 100F capacitor that is quite compact, though they have
voltage ratings between 2V and 2.7V. I think
there's some sort of square-cube thing going on here that
makes ever-increasing values of capacitance ever huger.
Not really. For a given
technology, the volume is roughly linearly
related to the product of the capacitance and voltage.
9 Jun
9 Jun
2:51 a.m.
Nico de Jong wrote:
Well, here's a rough off-the-cuff comparison of the two as energy storage devices:
- If a 12V 40Ah battery supplies 40A for one hour into a load,
then the load resistance is 12V/40A = 0.3 Ohms.
- To achieve an RC time constant of 1 hour with 0.3 ohm R requires C of:
1h * 60m/h * 60s/m / 0.3 Ohms = 12000 Farads.
(There is a lot to criticise in this comparison, notably that the RC time
constant involves a significant drop in the voltage and hence current.
A better comparison would utilise energy equations but then I'd have to look
them up.)
With that said, a battery is not a capacitor. They have a gross similarity as
electrical energy storage devices but the electrochemical reactions of the
battery result in very different electrical characteristics and response than
does the 'pure' electrostatic nature of a capacitor.
Roger Holmes wrote:
I wonder how many Farads a car battery helds (incidentally, how come MF does not mean Mega
Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion.
3:06 a.m.
On 8 Jun 2009 at 23:51, Brent Hilpert wrote:
With that said, a battery is not a capacitor. They
have a gross
similarity as electrical energy storage devices but the
electrochemical reactions of the battery result in very different
electrical characteristics and response than does the 'pure'
electrostatic nature of a capacitor.
Have you been following the mystery of eeStor? They claim a
capacitor with a better energy density than any secondary cell. They
seem to be using a high voltage (3Kv) on some sort of barium titanate
setup. It it's real, it'll be Very BIg News, but many think it's
unadulterated snake oil.
--Chuck
1:55 p.m.
New subject: (OT) batteries & e storage / was Re: IBM 029 progress
Chuck Guzis wrote:
Have you been following the mystery of eeStor? They claim a
capacitor with a better energy density than any secondary cell. They
seem to be using a high voltage (3Kv) on some sort of barium titanate
setup. It it's real, it'll be Very BIg News, but many think it's
unadulterated snake oil.
No, hadn't heard, I'll have to go look it up.
A year or so ago I heard a news interview about an aluminum/oxide fuel cell,
that is, the fuel is aluminum, handled in such a way that electrical
energy is released as it undergoes controlled oxidation. Haven't heard anything
since; struck me as sounds good in theory, not so much in practice and economics.
1:40 p.m.
Roger Holmes wrote:
I wonder how many Farads a car battery helds (incidentally, how come MF does not mean Mega
Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion.
12:52 a.m.
Warren Wolfe wrote:
Roger Holmes wrote:
You could probably beat 100F by building into a 55gal drum and designing
carefully.
Peace... Sridhar
(incidentally, how come MF does not mean Mega
Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion.
4:50 a.m.
On Tue, 2009-06-09 at 00:52 -0400, Sridhar Ayengar wrote:
Warren Wolfe wrote:
Not that carefully. a 100F 2.7V capacitor is about the size of your
thumb.
Gordon
Roger Holmes wrote:
You could probably beat 100F by building into a 55gal drum and designing
carefully. (incidentally, how come MF does not mean Mega
Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion.
8:58 a.m.
Gordon JC Pearce wrote:
On Tue, 2009-06-09 at 00:52 -0400, Sridhar Ayengar
wrote:
I was thinking of a waay higher voltage than that.
Peace... Sridhar
Warren Wolfe wrote:
Not that carefully. a 100F 2.7V capacitor is about the size of your
thumb. Roger Holmes wrote:
You could
probably beat 100F by building into a 55gal drum and designing
carefully. (incidentally, how come MF does not mean Mega
Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion. 
2:48 p.m.
Sridhar Ayengar wrote:
Gordon JC Pearce wrote:
Remind me not pick up any steel drums made by Sridhar. :)
On Tue, 2009-06-09 at 00:52 -0400, Sridhar
Ayengar wrote:
I was thinking of a waay higher voltage than that.
Peace... Sridhar
Warren Wolfe wrote:
Not that carefully. a 100F 2.7V capacitor is about the size of your
thumb. Roger Holmes wrote:
> (incidentally, how come MF does not mean Mega Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion.
You could
probably beat 100F by building into a 55gal drum and
designing carefully. 
2 p.m.
New subject: Farads (Was: IBM 029 progress
(incidentally,
how come MF does not mean Mega Farad)
Since the largest capacitor I have ever heard
of is 100 Farads, it
really doesn't seem likely that there will be any confusion. 
2:17 p.m.
New subject: Farads (Was: IBM 029 progress
On Tue, Jun 9, 2009 at 11:00 AM, Fred Cisin<cisin at xenosoft.com> wrote:
Was "capacitator" ever a valid name?
It's what I used to say in 7th grade but I think I just read it wrong.
Somebody corrected me and I've only seen 'capacitor' since.
John
--
"I've tried programming Ruby on Rails, following TechCrunch in my RSS
reader, and drinking absinthe. It doesn't work. I'm going back to C,
Hunter S. Thompson, and cheap whiskey." -- Ted Dziuba
2:22 p.m.
New subject: Farads (Was: IBM 029 progress
On Jun 9, 2009, at 2:00 PM, Fred Cisin wrote:
Would a "thunder cloud" be considered a capacitor?
Of course, with the other "plate" being the earth.
(incidentally, how come MF does not mean Mega Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion. If so, how many MF would lightning take?
LOTS. Think plate area. :)
Was "capacitator" ever a valid name?
I don't believe so, but many of people have used it as such.
-Dave
--
Dave McGuire
Port Charlotte, FL
2:46 p.m.
New subject: Farads (Was: IBM 029 progress
Dave McGuire wrote:
On Jun 9, 2009, at 2:00 PM, Fred Cisin wrote:
Would a "thunder cloud" be considered a capacitor?
Of course, with the other "plate" being the earth.
Without some numbers, I'm not entirely sure about that. Large plate area but
also a rather thick dielectric and hence large plate separation. Yes, a
tremendous amount of energy is released in a lightning strike (aka dielectric
breakdown) but that comes with a very high voltage. C=Q/V, energy is also a
function of Q & V, large amount of energy does not necessarily imply large C.
(incidentally, how come MF does not mean Mega Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion. If so, how many MF would lightning take?
LOTS. Think plate area. :) > Was "capacitator" ever a valid name?
Sounds like a political leader or a type of potato chip.
2:52 p.m.
New subject: Farads (Was: IBM 029 progress
On Jun 9, 2009, at 2:46 PM, Brent Hilpert wrote:
Of course, with the other "plate" being the earth.
Without some numbers, I'm not entirely sure about that. Large plate
area but
also a rather thick dielectric and hence large plate separation.
Yes, a
tremendous amount of energy is released in a lightning strike (aka
dielectric
breakdown) but that comes with a very high voltage. C=Q/V, energy
is also a
function of Q & V, large amount of energy does not necessarily
imply large C.
Hmm yes, I agree. I'd love to do a SPICE simulation of some sort
of oscillator using a cloud/earth capacitor. :)
-Dave
--
Dave McGuire
Port Charlotte, FL
>
(incidentally, how come MF does not mean Mega Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion.
Would a "thunder cloud" be considered a capacitor? If so, how many MF would lightning take?
LOTS. Think plate area. :) 
3:58 p.m.
New subject: Farads (Was: IBM 029 progress
On Jun 9, 2009, at 11:52 AM, Dave McGuire <mcguire at neurotica.com> wrote:
On Jun 9, 2009, at 2:46 PM, Brent Hilpert wrote:
Without some numbers, I'm not entirely sure about that. Large plate
area but
also a rather thick dielectric and hence large plate separation.
Yes, a
tremendous amount of energy is released in a lightning strike (aka
dielectric
breakdown) but that comes with a very high voltage. C=Q/V, energy
is also a
function of Q & V, large amount of energy does not necessarily
imply large C.
Hmm yes, I agree. I'd love to do a SPICE simulation of some sort
of oscillator using a cloud/earth capacitor. :)
Then add in a flux-capacitor / delorean simulator to test out Doc
Brown's theories on time travel...
>> (incidentally, how come MF does not mean Mega
Farad)
> Since the largest capacitor I have ever heard of is 100 Farads, it
> really doesn't seem likely that there will be any confusion.
Would a "thunder cloud" be considered a capacitor?
Of course, with the other "plate" being the earth.
If so, how many MF would lightning take?
LOTS. Think plate area. :) -Dave
--
Dave McGuire
Port Charlotte, FL
4:39 p.m.
New subject: Farads (Was: IBM 029 progress
Josh Dersch wrote:
Then add in a flux-capacitor / delorean simulator to
test out Doc
Brown's theories on time travel...
That goes with the other thread ... Earliest mobile computer :)
Notice that only in Star trek/Bab 5 are computers used ... Every other kind
of Si-Fi is all analog. :)
Ben.
4:46 p.m.
New subject: Farads (Was: IBM 029 progress
That goes with the other thread ... Earliest mobile
computer :)
Notice that only in Star trek/Bab 5 ?are computers used ... Every other kind
of Si-Fi is all analog. :)
"Just what do you think you're doing, Ben? Ben, I really think I'm
entitled to an answer to that question."
--
Will
5:06 p.m.
New subject: Farads (Was: IBM 029 progress
bfranchuk at jetnet.ab.ca wrote:
Josh Dersch wrote:
Wot? Let's just take the other major SF franchise, Star Wars.
'Droids. Digital, no? Same for MANY others, if not all. Heck, what SF
were you thinking of that's all analog? Forbidden Planet?
Warren
Then add in a flux-capacitor / delorean simulator
to test out Doc
Brown's theories on time travel...
That goes with the other thread ... Earliest mobile computer :)
Notice that only in Star trek/Bab 5 are computers used ... Every
other kind
of Si-Fi is all analog. :)
5 p.m.
New subject: Farads (Was: IBM 029 progress
Dave McGuire wrote:
On Jun 9, 2009, at 2:46 PM, Brent Hilpert wrote:
Without some numbers, I'm not entirely sure about that. Large plate
area but
also a rather thick dielectric and hence large plate separation. Yes, a
tremendous amount of energy is released in a lightning strike (aka
dielectric
breakdown) but that comes with a very high voltage. C=Q/V, energy is
also a
function of Q & V, large amount of energy does not necessarily imply
large C.
Hmm yes, I agree. I'd love to do a SPICE simulation of some sort of
oscillator using a cloud/earth capacitor. :)
I'm just grateful the dielectric is self-healing after breakover....
Warren
>> (incidentally, how come MF does not mean Mega
Farad)
> Since the largest capacitor I have ever heard of is 100 Farads, it
> really doesn't seem likely that there will be any confusion.
Would a "thunder cloud" be considered a capacitor?
Of course, with the other "plate" being the earth.
If so, how many MF would lightning take?
LOTS. Think plate area. :)
6:17 p.m.
New subject: Farads (Was: IBM 029 progress
On Thu, 2009-06-11 at 15:25 -0600, bfranchuk at jetnet.ab.ca wrote:
Warren Wolfe wrote:
"Awww fsckit, missed *again*..."
Gordon
I'm just grateful the dielectric is
self-healing after breakover....
It is the voice from the clouds that scare me ...
*This is your first Warning* 
6:15 p.m.
New subject: Farads (Was: IBM 029 progress
At 11:00 AM 6/9/2009 -0700, you wrote:
Would a "thunder cloud" be considered a capacitor?
If so, how many MF would lightning take?
Was "capacitator" ever a valid name?
I wonder if Al K has heard this story.
When my good friend Don was still alive, he'd tell the story of working for
a hospital many decades ago. He'd get calls from med techs and nurses about
defibrillators that no longer worked. Some uncluefull person playing with
them would stick the business end of the paddles together and rub them
around, like he's seen on TV. Problem is, the uncluefull one would then
bump the button that discharges the paddles.
One time, when someone asked what was wrong with the unit, he mentioned
that the big capacitor inside got blowed up when the paddles were
discharged into a short circuit.
Sure enough, next time she called and forever after, she'd say, Can you fix
this defib? I think the cazapiter is fried again.
-T
-----
865. The fear of the LORD is the beginning of wisdom; all who follow his
precepts have good understanding. To him belongs eternal praise. --Ps
111:10 (NIV)
--... ...-- -.. . -. ----. --.- --.- -...
tpeters at nospam.mixcom.com (remove "nospam") N9QQB (amateur radio)
"HEY YOU" (loud shouting) WEB: http://www.mixweb.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
(incidentally,
how come MF does not mean Mega Farad)
Since the largest capacitor I have ever heard
of is 100 Farads, it
really doesn't seem likely that there will be any confusion. 
11 Jun
11 Jun
9:19 a.m.
New subject: Farads (Was: IBM 029 progress
Fred Cisin ????????:
Was "capacitator" ever a valid name?
Capacitaters are quite starchy and difficult to charge without
exploding. But done right, they're also tasty with butter.
==
To iterate is human, to recurse, divine.
--
jd
9 Jun
9 Jun
3:15 p.m.
Sridhar Ayengar wrote:
You could probably beat 100F by building into a 55gal
drum and
designing carefully.
Gordon JC Pearce wrote:
Not that carefully. a 100F 2.7V capacitor is about the
size of your thumb.
Sure, a product with a huge amount of engineering behind it and
significant manufacturing technology can be made like that.
For a do-it-yourself capacitor design, I'll be extremely impressed with
someone that makes a true 100F capacitor from raw materials, that has
less than one ohm ESR, and is ANY size. Allowing the volume to be 55
gallons does not make it that much easier.
Eric
3:08 p.m.
Sridhar Ayengar wrote:
You could probably beat 100F by building into a 55gal
drum and
designing carefully.
If by "designing carefully" you mean putting a lot
of parallel supercaps
inside the drum, yes.
If you mean designing an actual capacitor yourself out of materials you
machine yourself with resources available to a serious hobbyist, most
likely not. Making high-value capacitors is NOT easy, which is why
capacitors >1F didn't become generally available until the mid-1980s.
Eric
1:37 p.m.
Roger Holmes wrote:
I rememebr seeing a 2.7kF (yes, kilofarad) capactior in a catalogue, but
I think it's now been discontinued... I've never seen anythlng larger.
The reason MF (or MFD) was used for microfarad was, I guess, they
couldn't print/stamp lower case or greek letters onto the components.
I've also seem MMFD (micro micro farad) for what is more commonly called
pF.
I guess this is one reason why mF (millifarad (1000uF)) is not commonly
used. It would casue too much confusion with the old MF.
Anyone else rememebr an upside-down Omega being used for megohms? And I
am sure I've seen 'M' being used for 1000 In resistor values in some old
service manuals (maybe RCA). Caused a lot of confusion to me at first
(why does this valve have a 47 meg resistor feeding the screen grid???
Oh, they mean 47k..)
-tony
(incidentally, how come MF does not mean Mega
Farad)
Since the largest capacitor I have ever heard of is 100 Farads, it
really doesn't seem likely that there will be any confusion.
5:44 p.m.
New subject: Supercaps (was Re: IBM 029 progress)
Tony Duell wrote:
> I rememebr seeing a 2.7kF (yes, kilofarad)
capactior in a catalogue,
> but I think it's now been discontinued... I've never seen anythlng
> larger.
>
Warren Wolfe wrote:
Good Lord.... How big was that thing? And, what
voltage?
Possibly an Epcos B49410B2276Q000, now obsolete. It was 75mm diameter
by 150mm tall, rated at 2.5V (2.8V surge).
Epcos made supercaps up to 5kF, but they appear to have gotten out of
that market. Capacitors up to 100F are readily available from other
vendors; I haven't looked for alternate sources of larger values.
Eric
12 Jun
12 Jun
2:54 p.m.
Tony Duell wrote:
It was something like 2.5V (I know it wasn't 3.3V or 5V, alas). It wasn't
that large, IIRC it was smaller than a car battery, say. It also wasn't
cheap (over \pounds 150.00), which is why I never bought one.
-tony
> I rememebr seeing a 2.7kF (yes, kilofarad)
capactior in a catalogue, but
> I think it's now been discontinued... I've never seen anythlng larger.
>
Good Lord.... How big was that thing? And, what voltage?
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