AN920

I hardly ever use wrist bands. The few occations where I used one I just clamped it to cct ground. Some people like to work on a anti-static mat which is just a very high impedance to earth. How did your LDR circuit turned out?

If you don't know what to do with the spare amp put it at the top as another buffer by breaking at the blue line. Circuits can quicly get out of hand and you end up with 10 opamps! ;D

You could also try this clamp idea. It will require 1 extra opamp. This will prevent your offset value from going higher than your LDR value and will then prevent the opamp going negative. As long as the offset is lower than the LDR value it will have no effect on the circuit. Just a idea. If you want a visual indication when the offset is adjusted below the LDR value add the extra LED and resistor.

look here http://www.radiometrix.co.uk/index.htm They have agents many places. In the US it is sold by Mouser and the cheap ones is about $10

You can try this. Play with the RxC constant to reduce flicker response. Last variation will allow you to use smaller C value

This what I mean. Also I would add a buffer to prevent any loading by the B2 on the LDR when B2 goes low resistance which will place R6 in parallel with R10.

Your diagram does not indicate how the sliders are connected. As it is drawn it does nothing when you vary the pot. Indicate the direction that slider B1 will move in respect to B2 when adjusted. This is all important. Maybe fix the drawing to avoid confusion.

Dual gang pots are normally made for audio and will likely be log not linear. This could be why you see the rapid increase at the end. I think if you look at the pot markings there is a B for linear or A for audio or log. more here http://sound.westhost.com/pots.htm#using

Your scope will give 2 X the reading because it is not terminated into 50 Ohm Your scope will also read lower because the 210 has a 60MHz BW meaning that the reading at 60 MHz will be up to 3dB lower. A scope of >= 100Mhz will give a more accurate reading.

It is called a Shockley Diode http://www.allaboutcircuits.com/vol_3/chpt_7/3.html 2 of these in anti-parallel used to make a diac

go to www.molex.com under "product type" you will find it there. Digikey used to keep some molex stuff

I have seen similar parts with the typical blue color in the past by Siemens. Also BMW - Germany- Siemens, make sense?

"This inverter is of a traditional ferroresonant design using large step-up transformer" This type of transformer to obtain a sine output is hardly used anymore because of high cost, bulk and is also not very efficient. http://www.allaboutcircuits.com/vol_2/chpt_9/6.html "Ferroresonance" is a phenomenon associated with the behavior of iron cores while operating near a point of magnetic saturation (where the core is so strongly magnetized that further increases in winding current results in little or no increase in magnetic flux). Normally, core saturation in a transformer results in distortion of the sinewave shape, and the ferroresonant transformer is no exception. To combat this side effect, ferroresonant transformers have an auxiliary secondary winding paralleled with one or more capacitors, forming a resonant circuit tuned to the power supply frequency. This "tank circuit" serves as a filter to reject harmonics created by the core saturation, and provides the added benefit of storing energy in the form of AC oscillations, which is available for sustaining output winding voltage for brief periods of input voltage loss (milliseconds' worth of time, but certainly better than nothing). Unfortunately, these devices have equally noteworthy disadvantages: they waste a lot of energy (due to hysteresis losses in the saturated core), generating significant heat in the process, and are intolerant of frequency variations, which means they don't work very well when powered by small engine-driven generators having poor speed regulation. Voltages produced in the resonant winding/capacitor circuit tend to be very high, necessitating expensive capacitors and presenting the service technician with very dangerous working voltages. Some applications, though, may prioritize the ferroresonant transformer's advantages over its disadvantages. Semiconductor circuits exist to "condition" AC power as an alternative to ferroresonant devices, but none can compete with this transformer in terms of sheer simplicity. "In general, ferroresonant UPSs that use transformers are often larger in size and produce heat which can impact sensitive components in a computer and batteries in the UPS". http://www.natpow.com/power101/ferro%20ups.htm

Product Description 2K Ohm 2 Watt Pot 2K ohm by PEC/Canada. Perfect for LM317, LM350 circuits. 3/4" long shaft. With hardware. RES1352.... Price: $2.49 Part No.: RES1352 Put resistor in parallel to get value down to 500R 500 Ohm 10 Turn Pot Price: $9.95 Limited availability. 2 watts Part No.: RES1355 In Stock: Yes

100nF capacitor made by Siemens

Here is something interesting. I guess it depends which databook you look at

I think the block diagram is a bit misleading. You get a better idea from the logic diagram which shows a combination of inverters used to obtain Q and Q_bar Also the way they drawn it may be a way of indicating that the FF has buffered outputs. Will be difficult to tell without the details of the internals.

MP, The way I read it is that the %duty at Q and Q_bar will be 50% and that the signal at the oscillator output is not guaranteed to be 50%

Read here http://www.electronics-lab.com/forum/index.php?topic=4741.56

I am building a FM stereo transmitter from a kit and need to measure my modulation or also called deviation when on air. Where can I find a circuit to do this? The only thing I found was here http://www.edmdesign.com/mic.htm where they use a small radio. Any idea what the "additional electronics" would be and how they do it? If I use the VU meters on a FM receiver, how can I calibrate it at 75kHz modulation?

Yes that might be the reason. I was searching for prices on the 2n3866 and 2n4427 and found Mouser have them at $1.60 and $2.00. Unable to find any sale of the Bfs22a. The only ones are the component brokers that wants you to ask them for a quote. I tried them before and boy they want you to spend minimum $200 or more. I hate that! Even better from JDR! $1.00 http://www.jdr.com/interact/item.asp?itemno=2N3866 Also found some 2n3866A. What will be the difference from a 2n3866?

I wonder why this circuit from Harry using very much the same transitors only produce highest 180-360mW?? http://web.telia.com/~u85920178/tx/v7_proj.htm

Maybe, he is very quiet

Think sssaaa will be happy now? ;D Hey sssaaa what you say?

What is the power of this micromitter? Only 16 channels? This can be a problem where the band is very full