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.
We found this circuit in an old documentation. The indicated solenoid is of low current type,...
This commercial circuit of 3 transistors was found in Japanese documentation from the 1960s. The...
This circuit was found in National Semiconductor documentation from the 90s. The circuit uses two...