Electronics Forum / Basics / November 2006

I have an Instek GDS-2202 digital storage oscilloscope. I am trying to
figure out how to setup my scope to minimize the pick up of stray 60Hz
mains signal. If I change my scope's vertical sensitivity to 20mV/div,
then I can see the 60Hz signal. The signal's amplitude increases even

I have a silicon photodiode and I am trying to characterize it.  When I
measured the currents generated in photovoltaic mode (PV) of operation
(without applying a bias) and in photoconductive (PC) mode of operation
(applying a 5V reverse bias voltage), I noticed that the Signal to

Greetings group. I am a new member so please forgive me if I do or say
something that I shouldn't.
I have been asked to make a True / False quiz board. The board will
have 10 questions on it with two miniature push buttons below each

Hello once again!
I'm reading about Texas Instrument's Single Supply Opamp Circuits
reference guide. I was wondering if there is a way to create a
half-supply voltage reference that is completely dependent on the input

I've got a PIC16F627 and two crystals. One is 12MHz, the other is
20MHz. The 12MHz one says it needs a load cap of 32pF, the 20MHz one
says it needs 30pF. What does this mean!??
The circuit in the PIC datasheet has two caps going from either side of

I am looking to get a set of  logic probes and need some
recomendations.  The only set I see with the current tracer is the old
hp 547a.  There is a set on ebay for $299.00 which seems high.  I
mainly need the tracer.  Is there another Current tracer out there that

I have a Pansonic stereo system with separate high and low speaker
terminals.  There is only one stereo power amp ... thus it is not a true
bi-phase arrangement.  I can't find the answer to how the hybrids work, so I
am posting my guess here.

OK, first of all, this is more a learning exercise for me (my
background is with computers, but I am wanting to acquire some
electronics skills), although it does have a practical use, so please
bear with me. In my house we have shelf-type-things where folded

Between microprocessors and breadboard on education and studies, I
would like to introduce the unexpensive and convienent-using breadboard
to asisst you to have circuit test.
By the way, the price of breadboard in China now is only half of the

I tried Googling but all the formula for finding 555 timer frequency
is based on known capacitor and resistor values to find frequency.
I need to build a monostable timer to get 140Hz.  I could throw in a
random capacitor and one resistor but my algebra skill is rusty (no

I just bought a bunch of 12V relays for some, auto-related uses
(alarms, horns, etc.). Well, I need to know the wiring diagram, or more
simply what wire goes with what.
For instance, I want to add a new horn relay, using a switch, when

I'd like a 3-4' audio cord between my headset and PC. Anyone know where I
can find one. Most at 6'. 1/8" dia.
         Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
             (121.015 Deg. W, 39.262 Deg. N) GMT-8 hr std. time)

I don't like phones especially. They make an annoying ringing sound,
which usually isn't intended for me. (I have a wife and daughter). I
have an answering machine which takes care of part of the problem, but
there's a specific problem I'd like to solve that I'm sure other people

The motor on my commerical furnace (heat+air) went bad. I took the
motor out. The existing motor was an Emerson motor, 3/4HP,1075 rpm,6.3
amps,230volts with no capacitor. The existing motor is a 2 speed motor.
The motor had 4 wires (brown,black,red,orange). All these wires were

I need to convert a 32 bit binary number to gray code. i know how to do
it bit by bit, but i need to do a function to do it, so that i don't
need to repeat code 32 times. Can anybody help me?
Thanks