Blown Fuse Alarm (CB6109E)

We found this circuit in a 1967 Electronic design. However, it can be easily implemented even today as it uses only common diodes.

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Light disturbance detector (CB8522E)
This circuit is based on the light comparison of two LDR sensors. We found it in a 90s Popular...
Ultra Simple Crystal Radio (CB18425E)
We found this crystal AM radio using a germanium diode in a Japanese magazine in 1967. The circuit...
Automatic Crossing Light (CB14947E)
When a model train crosses a level crossing, interrupting the light on the sensor, this circuit...