This circuit was found in the March 1995 issue of Electronics Now magazine. The circuit requires a symmetrical power supply, and the FET is a common general-purpose type.
This circuit is from an American publication from 1974. The circuit can be designed with PNP BC558...
This “people detector” with pyroelectric sensor was found in the April 1991 issue of Radio...
Found in 1968 documentation this amplifier can be designed based on current transistors. Observe...