This circuit was found in a Electronics World of 1968. The integrated circuit is the MC1320P from Motorola, uncommon today.
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...