This power supply for gas laser (HeNe) was found in a 90’s Popular Electronics. It generates from 1300 to 1500 V using common components.
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...