Simple 5V regulator (CB8815E)

This simple 5.6 V regulator circuit was found in a 1966’s Philips. The zener can be changed to obtain other voltages.

High Impedance Analog Voltmeter (CB19636E)
Common operational amplifiers can be used on this circuit. The resistor with no value in series with...
Photo Relay with the 2N3055 (CB12035E)
Carefully removing (and a lot of work) the cover of a metallic 2N3055 to expose its joints it...
Solid State Capacitor (CB16939E)
The circuit shown, found in French documentation from the 1970s, functions as a variable...