Electronics Forum / Basics / December 2003

Could I jump-start my Ford Escort with a 16VDC welder?  Actually, the welder
is 32VAC, 100-amp, but if I hook up some diodes, maybe? Or maybe it's not a
good idea? But just hypothetically, would it work?  I wake in the morning
with a dead battery and late for work. It's impossible ...

I've built a few projects using Rabbit RCM2200's and various ICs,
LEDs, etc, and have used a variety of power supplies:
- old PC supplies (old Mac laptops have nice compact ones)
- open frame switching supplies from Jameco

I have two stereo recievers that are dead after a power spike
(high-low on the pole on the corner of my block). I was hoping that it
would be a simple matter of replacing a blown fuse, however, when I
opened them up the fuses were fine. Both the one near the AC cord and

I want to run a Mini-ITX PC Motherboard off of a 12 volt
UPS Battery ( for a robotic platform )
The motherboard is currently connected to a DC/DC converter
and runs off of a 12 volt, 4.5Amp power brick. The DC/DC converter

I was wondering if anyone here has made a cordless headset with a
working mic as well? Using existing parts.
I am curious as I use a lot of internet phone, and It sucks being tied
down to the computer while speaking.  Is it possible? Anyone done it?

i was recently working on a guitar amp (not plugged in, or hooked up to
any power source) and got a nasty shock.  I always heard putting a metal
 screw driver with a non conductive handle between the two prongs on
the power chord will discharge whatever voltage that is left in ...

Does anyone here has a schematic for a voltage convertor/adapter hat
allows household items such as a Video Camera / laptop to be powered
by your vehicle cigarette lighter?

DC current meter could measure DC currents. But is it possible to use a DMM
AC current meter (rated 1-1000A) to measure current draw on an alternator's
DC output to see if it could put out 30A on a Honda automobile?
TIA

Dear Group,
I have schematic that I found on the web it was designed for US 120V mains.
What
do I need to do to convert it for UK 240V?

First a desciption of what I'm trying to do (sorry if it is
confusing):
I'm trying to make an LED driving circuit that will change (8) groups
of (8) LEDs (turn one group on and another off) whenever a beat is

I need some ideas for one session projects with some 6 year olds. I
cant think of much, only those wiggly wire games where you try and get
the loop round the bent wire or it goes bzzz.
Maybe thats the thing to do?

Could someone explain the reason why a SCR or Triac need a minimum load or
current level to conduct?
I understand (at least I think I do :-]  ) the circuitry necessary to
utilize the component, but I'm having a little difficulty understanding why

Is it the case that two 12 volt zeners in series will act like a 24 volt
zener?
Thanks,
Bill

Hi group.
I've always used a multimeter on a trial and error basis, till I get a
reading that looks like what I should get.  I think it's time now that I
try and understand what's going on though.  As such, I've composed a

Is there a "classic" diode? One that is designed to do only what diodes are
famous for - only allow current to flow in one direction? I'm guessing that
it's the 1N4001 - because that's the diode I see used the most. But I could
also be completely off. What do you think? Thanks!