This circuit uses a diode as a radiation sensor. The operational ones are old because the publication is from the 80's, but modern low voltage equivalents can be tested.
This reflex receiver for the mid-wave range employs germanium transistors of the time. We found it in...
The circuit shown timing the drive of a motor using an optical coupler. The diode bridge can be...
A new version of the previous circuit triggered by the negative transition of the input signal is...