This circuit is an improvement over the previous one, using the same capacitor system as a sensor. We also found it in Radio Electronics from the 80s.
Using 4 operational amplifiers this circuit generates 4 different tones. The circuit is from an...
This circuit, which appears at various points in this section and on the website with minor...
This circuit also makes use of a field effect transistor (JFET) which can be the BF245 and has an...