We found this battery eliminator in a Radio Electronics magazine from August 1974. The transistor must be equipped with a heatsink and other voltages can be achieved by replacing the zener.
This circuit is from the National Semiconductor Audio Handbook. The amplifier operates with 6 V...
This switched filter was found in the 1969 documentation. The FET should be current-matched and eventually...
This independently charged circuit was found in a 1969 EEE. The operational amplifier supports a...