This anti-theft circuit was found in a 1985 documentation. It uses common components that can still be found easily. The relay is 12 V and the circuit has timings of 3 minutes and 20 seconds.
This is the modern version of the Galena radio in which the detector is a germanium diode (which can...
This old 4-channel circuit was found in the December 1994 Electronics Now magazine. The circuit uses...
This second-order low-pass Salen-Key filter was obtained from an American 1980s documentation. Formulas...