Basics

Integration w/o Smoothing; Demodulate, Integrate and then Take the Quotient
On Fri, 19 Feb 2010 21:02:51 -0800 (PST), Bret Cahill <BretCahill(a)peoplepc.com> wrote: There is no reason to smooth after demodulation in some low noise lock in amplifier situations. If you are taking the quotient of two signals that are identical except for magnitude and noise, i.e., shape, ... 20 Feb 2010 01:28

Transistor question -theory
Hi, I have been analyzing the 'how to' of a transistor recently. Electron flow, holes, dope material etc... I still do not understand why a transistor can be reversed, anyway reverse based from all those web pages. They all show a transistor either N-P-N or P-N-P, lets take NPN or emitter-base-collector why can... 22 Feb 2010 16:25

Integration w/o Smoothing; Demodulate, Integrate and then Take the Quotient
There is no reason to smooth after demodulation in some low noise lock in amplifier situations. If you are taking the quotient of two signals that are identical except for magnitude and noise, i.e., shape, frequency and phase angle, simply low pass integrate each signal after each is multiplied by the reference.... 5 Mar 2010 17:21

18650 li-ion
Could some one explain the protection mechanism on some 18650 li-ion batteries and why they do not work with some xenon or led torches? ... 20 Feb 2010 13:32

Load Capacitance
Hello Everyone, I have a couple of surplus crystals, 10.7 MHz. Is there a way to find out the Load Capacitance for them ? The people I bought them from don't know. What I am doing is a "Can I make this work" project. I have a stable audio oscillator, a working varactor and an iffy collpits, crystal, RF o... 17 Feb 2010 23:34

Stepper motor controller current limiting question
Hello, all. I'm trying to build my first stepper motor controller and I have two questions. In trying to learn about stepper motors and controllers I read the document AN907 from Microchip among other documents and sites: http://ww1.microchip.com/downloads/en/AppNotes/00907a.pdf In that document the author writ... 3 Mar 2010 18:40

why no corona discharge from power lines?
Something i've never puzzled out.. If I make a 14kv generator (and I have made a few high voltage generators in my time), I get constant corona from its unattached output. Why do the 14kv power lines strung around town not do the same? I know sometimes there is just a little bit of discharge around power l... 17 Feb 2010 19:04

Asking about Amplitude Shift Keying
Hello group, I posted a screen capture of an image showing a basic Amplitude Shift Key modulation: http://imgur.com/Ahwya.jpg The image shows the a diagram and equation. The equation is ASK(t) = s(t)*sin(2*pi*f*t). I assume s(t) is the baseband signal and sin(2*pi*f*t) is the carrier frequency. In the imag... 19 Feb 2010 15:31

About AC adapters...
I want to use electrolysis to separate chemicals, but electricity isn't much my domain! Now, instead of using a battery, I read (but didn't tried yet) that I could simply use a AC converter. So I had an old CD player "plug", which reads the following: Ac Adaptor Input: AC120~60Hz 5.3 W Output: DC 4.5V=-= 600 m... 18 Feb 2010 11:42

Voltage rating of keyboard cable?
A question: Have one of those older style keyboard cables in hand; this one is NOS (i.e. brand new, old stock). It has a 5 pin (large) DIN plug at one end. Anybody got any idea of the maximum 'voltage' rating; of the wire and the plug? Not worried about the 'current' (amperes) rating; only the maximum safe vol... 14 Feb 2010 12:55