Similar to other circuits found in this section, this circuit is from a 1996 Electronics World; FET is general-purpose and the output circuit must be resonant at 100 kHz.
Two tone siren (CB9085E) This circuit was found in a 1980’s Radio Electronics. The signal must be...
Found in an American publication from the 1980s, this circuit can be found in commercial sound...
We found this circuit in an 80's Radio Electronics. The circuit uses a PTC sensor and an LED...