Charger protection relay (CB26312E)

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

Digital thermometer (CB9486E)
This 3 and-a-half digit circuit was found in a Teledyne documentation from the 90s. The circuit uses...
Transistor Constant Current Source (CB13410E)
We found this circuit in an English publication in 1976. The circuit is based on the use of a...
Low Pass Filter with Transistors (CB19699E)
This filter of two transistors has the cutoff frequency determined by the formulas next to the...