Audio Mixer with LM741 (CB25928E)

This circuit is from a Radio Electronics magazine from May 1989. The power supply must be symmetrical. The input channels can be changed.

Gain 1000 Sample and Hold (CB5960E)
This 80's circuit has been winning. It is a 1 000 gain sample and hold circuit and an offset...
Instrumentation Amplifier (CB4230E)
The purpose of this 1-transistor amplifier is to allow the use of a milliammeter in an application...
20 kHz ring counter (CB6138E)
We found this circuit in an old General Electric documentation. In fact, PUTs are not common...