This converter or inverter uses components that are still common. The transformer is the type found in old tube equipment. The power transistors must be mounted on heat radiators.
This experimental amplifier was found in the 1960 Mullard transistor reference manual. The...
This circuit from Motorola is from 1968, appearing elsewhere on this site. The transistors admit...
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...