Diode Tester (CB22137E)

This diode tester was found in an English publication from the 1980s. Transistors are general-purpose types of the time.

Voice Over Music (CB14852E)
When a voice signal enters this circuit, the volume of the music being played automatically...
3 3V power supply (CB21173E)
This circuit for 3.3 V logic circuits has a 5 V input and the maximum output current is on the...
Broadband FM FSK Receiver MC13055 (CB14569E)
We found this circuit in Motorola's 1990 Linear Databook. The component used is unusual. The...