Low Voltage Test (CB22158E)

This is a simple voltage tester for voltages from about 2V to about 15V with the indicated resistor and red LEDs.

Limited range control (CB7221E)
Suggested by General Electric in 1965 documentation, this circuit controls the current at a load...
Simple function generator (CB20950E)
Found in Popular Electronics from the 1980s, this circuit uses two operational amplifiers from...
Stereo preamplifier (CB20654E)
We found this circuit in a Hands-on Electronics from 1985. The circuit is based on common...