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 ultra-low noise amplifier and simple power supply was found in Analog Devices documentation from the...
This circuit was found in a 1970s documentation. The integrated circuit used is uncommon today....
This control was obtained in an old publication from 1985 and uses a triac, which today can be of...