Neon Fuse Blown Monitor (CB24104E)

This circuit was found in the January 1971 Radio Electronics magazine. It keeps the light flashing if the fuse blows.

Carbon Microphone Preamplifier (CB12905E)
This very old circuit, from a publication from the 1970s, uses a germanium transistor and two...
Touch Switch (CB16091E)
In the figure we have a very sensitive touch switch circuit. A touch of the sensor causes the...
Mini Central for Intercoms (CB18747E)
In fact, we can say that this circuit found in documentation from the 90s, consists of an intercom...