This VCA was found in the July 1988 issue of Radio Electronics magazine. It uses an OTA op amp and has its gain adjusted by the voltage at the gain input.
Suggested by the General Electric Hobby Manual of 1965 this circuit measures voltages from 0 to...
) The circuit in the figure uses an old OC71 germanium transistor. Performance depends on...
We find this circuit in an American documentation from the 80's. The circuit has the coil given by the...