Tunnel diode simple noise generator (CB23705E)

This circuit was found in Radio Electronics magazine from November 1960. The circuit is powered by a photocell of the time.

Trigger stretcher (CB12277E)
This circuit was obtained in a 1978 publication. The SCR may be the TIC106. What it does is act as a...
High impedance preamplifier stage (CB4683E)
In the figure we have a high input impedance stage with a general purpose PNP transistor. An NPN transistor...
Multi Loop Alarm (CB6414E)
We found this circuit in a Popular Electronics of the 90s. The circuit can be easily mounted...