Found in a 90’s Popular Electronics, this circuit can use other power MOSFETs. The transformer has a primary according to the desired continuous voltage at the output.
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...