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.
The integrated circuit used in this application is not currently common. The circuit is from 80s...
This circuit was obtained in an Electronic Design from the 90s. The circuit uses transistors from the...
This circuit hás a Power output of more than 1 W. It is used in small experimental or low power...