Motorcycle headlight monitor (CB9117E)

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

Digital Die (CB17098E)
This circuit is from 1997 documentation, based on the well-known integrated circuit 555 and 4017....
DC Motor Speed Control (CB12321E)
This circuit is from 1980 documentation. We can exchange the BC177 for a BC557 and the TIP41 must...
Single Voltage Reducer (CB16872E)
From different input voltages V, it is possible to reduce the voltage to several fixed values...