This 5 W transistor amplifier for the car was found in an English documentation from 1969. The transistors are from that time and the transformer is of a special type.
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...