This circuit was published in Radio Electronics magazine in June 1959. The circuit uses an inverter with transformer to generate the high voltage of the Geiger tube.
Found in the July 1993 Electronics Now magazine, this circuit provides an output voltage whose...
I found this circuit in a documentation for radio amateurs from 1975. The FET could be the BF245....
This 1-transistor reflex receiver was found in a 1963 publication. The coil is for the mid wave...