We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply need not be symmetrical. The FET in the feedback acts as an automatic gain control.
The two power steps below are intended for use with the SAA1027 stepper motor control but can be...
This circuit was found in a Texas Instruments’ publication. The circuit must be powered from dual...
This automatic battery charger was found in a Popular Electronics from the 90s. The circuit uses a...