Electronics Forum / Basics / February 2008

Hello Friends,
Check this website www.calculatoredge.com you will find several RF &
Microwave Calculator Tool, you do not need to learn the formula to
solve the equations, if you have inputs then you can just enter into

http://www.plsbuy.com/7_Digital_Photo_Frames.html
7" Digital Photo Frame D7010BA
Digital picture frame with high resolution LCD displays, plays photo,
music and video, Quality Digital Photo Frames... Product Type:Digital

I was considering putting a current shunt in my car to monitor current
draw from the battery.  I found a 200 A current shunt and was wondering
if that would be enough.  Obviously during normal operation I'm not
going to be pulling near that.  But during start I could draw

Has anyone ever created an electrical switcher that *mechanically*
allows one to switch between appliances that run on standard household
current?(ie: TVs, stereo, computer, ect).
If not, can I get ideas on what it would take to build something like

Can anyone direct me to a materials chart for referencing materials
for electrical contacts?(Providing something like that exists).
I've had no luck with Google, and since I'll need to make contacts for
several projects I'm trying to get a good idea about what material/s I

It was inevitable that if there were found to be serious flaws in our
physics and in our understanding of gravity or such things as
'momentum' these would be quickly revealed beginning in the early
1970s, when human beings first began to explore space.

If I'm sending a 60 Hz sine wave to an electromagnet (inductor), then
won't the current through the coil lag the input voltage by 90 deg?
So if the magnetic field depends basically on the current and the
number of turns, the pull of the magnet will lag the input voltage by

When I measured impedance of the RF system, I discoved decreasing
imaginary part(minus value). but!! it is minus value(like -5 -10
-12...) and the real part of impednace was incresed accoding to the
increasing power(13.56MHz). finally we find decreasing the impednce

Looking at the guts of a heating control timer. There is a small (34mm
X 86mm) Graphics LCD. The only identifying mark is a label which reads
TMGG12864K-02-VJ075
Id like to determine the supplier.

When I read about home automation in wikipedia. I found that the
transmission medium for ethernet and IEEE1394 was UTP/FO, and I do not
know what it is. Although I tried to google it, I can't find the
actual meaning of it. Can anybody explain to me in simple terms what

I would like to build a portable power supply for a 11" digital
picture frame.  The 9volt supply would need to last 6 hours,  Would I
be better off with 9 volt batteries tied together or use 1.5 volt
batteries tied together?

I have a quick question that has been puzzling me.  I am trying to
calculate the internal power dissipated inside an op amp.  One way of
doing this is to determine the power dissipated in the load of the op-
amp, then subtract that from the power delivered by a DC supply.  The

I know there must be a super-simple way to do this, but I keep getting
caught up in PLL stuff.
I have a simple square wave in the audio-frequency range.  I would
like to simply shift its phase for experimental purposes.  The output

How can I test a smt capacitor in "live" circuit with a oscilloscope?
Thanks.

I have an old clock (30 day windup) I want to power with  a weight
that automatically raises a couple inches every 4 hours so I don't
have to wind it. The clock will run with a 8 ounce weight hung on an
arm extending about 6 inches from the drive wheel. The main drive