Motorcycle headlight monitor (CB9117E)

This simple circuit was found in Popular Electronics from the 1980s. The circuit uses an LED as an indicator.

Infrared alarm (CB7238E)
Found in 1968 Mullard documentation, this circuit uses period components. The transistors are...
Voltage Multiplier (CB20184E)
In the figure we have a modified multiplier circuit that can operate with the sextuplicator with...
Low frequency converter (CB9336E)
This circuit converts signals from the 350 to 500 kHz band to the 4.36 to 4.5 MHz band, enabling...