Found in Unitrode documentation, this oscillator uses some unusual components today such as PU and the 3 M potentiometer. The power can be made with voltages around 15 V.
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...