21 Jul
2008
21 Jul
'08
9:03 a.m.
At 12:00 -0500 7/19/08, C. Sullivan wrote:
...I'm going to out on a limb here and assume that
you are trying to use
a variable power supply wall-wart with one of those little slider
switches on it to do different voltages (is that the Radio Shack #
270-1551?).
...
I have one like that. It works in many cases, but I'm not much of a
fan. See below.
...Worse, most cheap supplies of this
type will sag as the load exceeds the rated maximum: so while it might
indeed be 9VDC at 100mA, at 175mA of load it can drop to 7.5V or lower.
Worse yet... mine does the inverse. Plugging it in unloaded, with the
switch set to 3V, still lets the voltage rise to around 10V (as
indicated by my analog multimeter, so it's not *totally* unloaded).
That scares me. I'm sure any reasonable load would drag it down near
3V, but ... is there any silicon in my load that wants to not see
12V, even powered off?
A proper lab supply will allow you to
give anything you find the RIGHT power, cleanly, and with overcurrent
protection that could save the device from frying.
Seconded, even though I have not done so myself (yet). While on the
topic, has anyone any experience with the Velleman integrated
DMM/Power supply/soldering iron?
http://www.vellemanusa.com/us/enu/product/view/?id=522812
Price isn't that great and all of the parts look sort of
beginner-level, but the compact size is appealing.
...Velleman makes a 1A kit power supply
that is more than adequate for a lot of this kind of stuff AND has the
bonus of being real easy and fun to build. It is $12.95 from Ramsey
Electronics (www.ramsey.com).
maybe http://www.ramseyelectronics.com ? The given URL advertises winches.
--
- Mark 210-379-4635
-----------------------------------------------------------------------
Large Asteroids headed toward planets
inhabited by beings that don't have
technology adequate to stop them:
Think of it as Evolution in Fast-Forward.
21 Jul
21 Jul
9:40 a.m.
Mark Tapley wrote:
While on the
topic, has anyone any experience with the Velleman integrated DMM/Power
supply/soldering iron?
http://www.vellemanusa.com/us/enu/product/view/?id=522812
The way I look at it, that's three bits of test gear that might potentially
get knocked out if one of them develops a fault. I'm not a fan of x-in-one
anything...
cheers
Jules
10:07 p.m.
On Monday 21 July 2008 12:40, Jules Richardson wrote:
Mark Tapley wrote:
Agreed!
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
While on the
topic, has anyone any experience with the Velleman integrated DMM/Power
supply/soldering iron?
http://www.vellemanusa.com/us/enu/product/view/?id=522812
The way I look at it, that's three bits of test gear that might potentially
get knocked out if one of them develops a fault. I'm not a fan of x-in-one
anything... 
11:36 a.m.
> While on
the
> topic, has anyone any experience with the Velleman integrated DMM/Pow=
er
supply/soldering iron?
http://www.vellemanusa.com/us/enu/product/view/?id=3D522812
The way I look at it, that's three bits of test gear that might potenti= get knocked out if one of them develops a fault.
I'm not a fan of x-in-=
one
anything...
Agreed! 
23 Jul
23 Jul
12:03 a.m.
Tony Duell wrote:
The latter doesn't apply to soemthing like a PSU
and multimeter in the
same box, of course. But some of these multimeters with all sorts of odd
ranges on them may look very nice, until the day when you have to measure
a voltage and a frequency at the same time :-).
Aha, but since they're usually less than a tenner, you buy two or even
three at the outset.
Gordon
21 Jul
21 Jul
11:15 p.m.
On 22 Jul 2008 at 1:07, Roy J. Tellason wrote:
You can't go wrong in buying the best basic tools that you can
afford. I'm still using my Weller WTCPT soldering station after more
than 30 years. It's still being made--and is arguably one of the
best conventional soldering irons out there.
Buy a good multimeter if that's what you need. Fluke DVMs seem to be
the digital version of the old Simpson 260 VOM.
If I needed to save money, I'd buy either one on the used market
without a second thought.
It's a good idea to stay away from "Swiss Army Knife" approaches to
fundamental tools. Reminds me of one of those little hammers whose
handle unscrews to form a screwdriver. Makes neither a good hammer
nor a good screwdriver.
Cheers,
Chuck
The way I look
at it, that's three bits of test gear that might potentially
get knocked out if one of them develops a fault. I'm not a fan of x-in-one
anything...
Agreed!
11:41 a.m.
On 22 Jul 2008 at 1:07, Roy J. Tellason wrote:
You can't go wrong in buying the best basic tools that you can
I guess it's time for me to say again :
'I am not rich enough to buy cheap tools'
The way I
look at it, that's three bits of test gear that might potentially
get knocked out if one of them develops a fault. I'm not a fan of x-in-one
anything...
Agreed! Buy a good multimeter if that's what you need.
Fluke DVMs seem to be
You do need a multimeter. And I'd rather have a reliable and accurate one
with a few ranges than a dodgy one with every range under the sun on it.
the digital version of the old Simpson 260 VOM.
In the UK, the Avo Model 8 is the classic analogue multimeter, to the
extent that AVO (an acronym for Amps, Volts, Ohms, of course) is often a
generic name for a multimeter. You can't go wrong buying one of those
provided it's not been misused (if second-hand).
If I needed to save money, I'd buy either one on
the used market
without a second thought.
I bought my Fluke 85 second-hand. I didn't really need it, but when I saw
a Fluke 80-series at a good price, I decided I wanted it...
-tony
22 Jul
22 Jul
5:29 a.m.
Chuck Guzis wrote:
It's a good idea to stay away from "Swiss
Army Knife" approaches to
fundamental tools. Reminds me of one of those little hammers whose
handle unscrews to form a screwdriver. Makes neither a good hammer
nor a good screwdriver.
The same is probably true of computer software... and hardware...
Sadly, that doesn't seem to be the way most of the world sees it. In any
environment (computing or otherwise) it's getting harder to find things that
do a single job only (but do it well and are built to last). But that's an OT
discussion...
cheers
J
(not quite awake yet)
5996
days inactive
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participants (6)
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ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
gordonjcp＠gjcp.net -
jules.richardson99＠gmail.com -
mtapley＠swri.edu -
rtellason＠verizon.net