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 1965 Philips circuit uses old company transistors like the BFY51 and BFY50. The circuit is...
This circuit is from an April 1991 Radio Electronics magazine. The circuit uses power MOSFETs and...
This small power supply for low currents (5mA) is suitable for power low-power TTL experimental circuits....