Charger protection relay (CB26312E)

This circuit was obtained from an Elektor magazine from the 90s. The circuit is to protect batteries while charging.

Ant transmitter (CB21870E)
This small FM spy transmitter uses three transistors with an RF amplification stage. We found it...
Temperature control (CB10168E)
This circuit makes use of a constant current source to control the temperature of a direct current...
High Current Timing Circuit (CB24442E)
This circuit with a voltage comparator is delayed by the capacitor. The circuit drives a power...