Taken from a 1967 RCA publication, this circuit maintains a low current in the battery when it is charged. The components are from the era.
This circuit was found in Motorola documentation from the 1980s. PUTs are not common components...
This low distortion circuit was found in a 1964 Electronic Design. The transistor admits...
This circuit is based on an uncommon Texas component today, as found in an American 1980s...