This circuit works as both an injector and a signal follower. We found it in the May 1994 issue of Electronics Now. The Z1 headphone must be high impedance.
This circuit was found in a 1967 Electronic Design. The circuit makes use of components from the...
This alarm circuit was found in April 1975 Radio Electronics magazine. The circuit uses a 12 V...
This latching alarm using simple contact relay was found in an English documentation from 1980. The...