This two-tone alarm siren was found in the January 1975 issue of Radio Electronics magazine. The power transistor can be changed and with it, Rx has values from 10 to 47-ohm.
This circuit, suggested by Texas Instruments, is based on the integrated TL497A, designed for...
In the figure we have the way to implement a sinusoidal oscillator with the 4093 IC. The component...
This circuit was found in an old American documentation. It can operate with signals from 40 Hz to...