Door buzzer or alarm (CB20492E)

This solar powered circuit was found in a 1991 documentation. The transistor is a general purpose NPN.

Current Source (CB5138E)
This constant current source is from the LM11's own factory manual used in the application. The circuit is...
Shorted coil indicator (CB23861E)
The purpose of this circuit is to detect whether a coil has shorted turns. The coil must be fitted...
Simple Diode Radio (CB19592E)
This medium wave radio must use a high impedance piezoelectric, crystal or magnetic phone and the...