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 is from the National Semiconductor Audio Handbook. The amplifier operates with 6 V...
This switched filter was found in the 1969 documentation. The FET should be current-matched and eventually...
This independently charged circuit was found in a 1969 EEE. The operational amplifier supports a...