Door buzzer or alarm (CB20492E)

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

Remote control feceiver (CB20573E)
This super regenerative detector circuit was found in an English documentation from 1963. The coil...
Offset Adjustment Sample and Hold (CB5958E)
We find this circuit in a 1980s documentation. The circuit can be applied to modern operators with...
Medium Wave Radio TH 66B (CB18372E)
This small medium wave radio was manufactured in the 1960s in Japan. The circuit is powered by 4...