Active audio filter (CB21770E)

This circuit was found in a 1977 documentation for radio amateurs. Integrated circuits are common operational amplifiers.

Voltage Controlled Current Drain (CB14212E)
The circuit below is a 1 mA current drain using a transconductance operational amplifier. The...
Wideband Oscillator or Amplifier (CB6347E)
This circuit was found in a NASA documentation from the 1980s. Component values are application...
Sine and square generator (CB20519E)
This circuit generates signals with two waveforms. The circuit is from a documentation from the...