This circuit with junction field effect transistors was found in documentation from the 1980s. The transistors can be MPF102 or BF245 and details of the coils are not given in the original.
The number of pulses produced by this circuit depends on the switch pressed. The circuit is from...
The signal itself captured by the (long) antenna serves to feed this simple experimental circuit....
Suggested by Motorola in a 1980s publication, this circuit is insensitive to changes in bias...