Electronics Forum / Basics / March 2004

Hi, I've been dabling with my car central locking, making my attempts
to integrate the alarm into the system. When I lock the doors remotely
with the key, the door pins go down (naturally), but when I press an
additional button on the key, it deadlocks the doors. There is a wire

I'm curious, the lightning rod system installed on a building
near by has only 3/8" dia cables leading to ground.
However I've read and seen photo's of galvanized fence
posts being melted from lightning strikes. How does the

I guys, first sorry for my english.
I am in a project where i need some 5x7 led matrix displays, but since
it has been impossible for me to find such component here in mexico
city, i want to create (or try to create) my own 5x7 led matrix, but

I'm looking to power a PC motherboard (Via mini-itx, M10000) with an
external DC-DC based power supply.  I can provide 12V, 5V, 3.3V and
5VBB but don't have -5V and -12V.   Do you know if motherboards
required these voltages in general?

I just got a new 15.6 V craftsman drill and noticed that when charging the
nicd batteries, the do *not* get warm at all, but in the instructions, it
says the batteries do get warm. They seem to be charged, but then they
already had juice in them when I charged them for the first ...

Dear Friends: Greetings: I am a retired attorney. A few years ago a
man came to me with a letter. He asked me to verify the fact that this
was legal to do. I told him I would review it and get back to him.
When I first read the letter my client brought me, I thought it was

I'm looking at the following website:
http://electronics.howstuffworks.com/digital-electronics4.htm
The two caps are connected in parallel. I'd like to know what's the
difference in terms of practical applications of connecting the caps in

i was just wondering that why despite of using the binary logic for 60
years now ( almost ) we are stilll stuck with that
i mean the way i see it 3^n is much greater than 2^n . i am talking
about the reduction in the size of equipments by a biblical factor

I'm looking for some information on making a wireless on/off switch.  The
on/off portion i mean is just a pulse to hit a flip flop on a circuit in
another room of a house.  I figured this is done on a simple IC or in a
simple circuit because i have a few devices that are simple ...

The noise detector can be found here
http://www.redcircuits.com/Page16.htm
I was wondering what benefits do we get by using
two op-amps in this circuit, because gain can also

Goodday!
I wanted to wire a warning light up in my dash board that tells me
when my stereo is on or off.  I know I need to reduce the car's
voltage down to a lower voltage....Is it possible to just use a

Hi, there:
Sorry for these two basic questions as I don't really know too much
about basic electronics... here is what I'm trying to do:
1. I found a dead AC outlet (see photos here:

We just added digital cable.  We would like to bypass the
cable box except when its needed.  What is the easiest way
of doing this?
Thanks,

I am looking for a circuit that will trigger a pulse after waiting for 60
minutes.
Thanks
Lee

   I'm thinking of making a low pass filter to use before an amp, so it can
drive a subwoofer. The most economic design seems to be the RC one. The
input is from a computer soundcard, the output is to a 10W amp driving a 4"
speaker. The questions are: