This distorter for musical instruments was found in a 80’s Hands On Electronics. The transistor can be any general purpose and the components can be changed to modify the effects.
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...