Transistor breakdown (CB21393E)

This inverse transistor breakdown circuit was found in a 1967 documentation. It applies to modern components.

Active Band Pass Filter MC33171 (CB15272E)
This circuit can also use other series operational amplifiers such as MC33172, MC33174, MC35171,...
Scanner squelch (CB9424E)
Found in Popular Electronics from the 90s, this circuit mutes a scanner's speaker in the absence of a...
Astable from 4 to 25 kHz (CB9246E)
This circuit was found in General Electric documentation from 1965. The transistors are from that...