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.
In the same way that we can regulate the voltage in the positive branch of the circuit, we can...
Based on the MC1488 or MC1489 operational amplifiers, this circuit has a 5000V isolation driving a...
Found in the July 1968 Supertena Bulletin of a Popular Electronics, this receiver makes use of the...