acron said:
Do you have a circuit layout or schematic of how everything goes together?
Start with the XR2206 sub-circuit:
http://www.google.com/imgres?imgurl...&sa=X&ei=2wwoTqnRAdKDsAKg-a07&ved=0CFYQ9QEwCA
or just Google "XR2206 circuits" to get the thre images for XR2206 circuits. The third circuit is the basic sine wave generator but there's a couple of differences in the screwdriver--
replace that .01uf cap with a 10 uF tantaum cap (even a 1 uF tantalum cap will do) and that 200 ohm resistor will be 150 ohms. Lastly replace that 50K pot on pin 3 with a 15K resistor. As I say, with this circuit, nothing is critical but you want to get a nice sine wave from 0 to 100 Hz. This circuit is actually a lot more simple than it looks; it took me about 20 minutes or less to knock it together.
Keep in mind, all of these sub-circuits will join together on a narrow piece of perf-board about 1/4" wide--- that's standard Radio Shack perf-board, four holes across-- so it takes some creative wiring to make all the parts fit; they will fit though. The three resistors are mounted behind the 2206 while the main cap (19uF tantalum) and th 150 ohm resistors are
mounted directly on top of the XR2206. The pot that controls the frequency is of course connected by wires and go to the back end of the screwdriver so the modulation frequency can be controlled manually. And since there'sonly room for on pot, that's the only one.
I might replace that pot with a rotary switch and fixed values but you may never know
if you might need a particularly frequency you don't have, so that pot provides flexibility ven if it's a bit awkward to tune all the time.
'Doc
Stay tuned for the 4046 VCO sub-circuit, no pun intended heh heh...