We found this circuit in an American documentation from the 90's. The circuit makes use of general purpose NPN transistors. The 0.005 uF (5nF) capacitors determine the frequency.
S1 changes the selection of the input signals in the circuit shown here. Other type of circuits,...
Found in documentation two years 80, this toy instrument uses an integrated circuit little...
With this configuration, greater power can be obtained from an operational amplifier, thanks to...