This circuit was found in an ancient American documentation. The power supply is not given, but we have the voltages used. The relay is sensitive type for high voltage.
This two-transistor constant current source is from a 1968 documentation. Modern equivalent...
This circuit was obtained in a 1977 technical documentation. The PUT admits equivalent and the...
We found this circuit in a 1997 documentation. Its purpose is to turn a load on or off using...