This high sensitivity circuit was found in the July 1992 Radio Electronics magazine. The circuit drives a buzzer, but a relay can be used to activate an external load.
This circuit uses a unijunction transistor in a different configuration to generate rectangular pulses at...
What this circuit does is generate a signal in a ladder pattern, containing steps in which the...
This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of...