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.
This circuit was obtained from a 1997 publication. It is an alarm that has a lock and a bistable...
This circuit was found in a 1997 magazine. It uses a CMOS 4060 circuit powered by 12 V which is...
This circuit was found in the December 1992 Radio Electronics magazine. Range depends on optical...