Flood alarm (CB7994E)

This circuit is from a 90s Popular Electronics. The transistors are of general use and the buzzer is a Sonalert type.

Two tone siren (CB9085E) This circuit was found in a 1980’s Radio Electronics. The signal must be applied to an amplifier stage. Capacitors can be changed to change effects. img src="images/stories/bc/144064"
Two tone siren (CB9085E) This circuit was found in a 1980’s Radio Electronics. The signal must be...
20 W per channel NEC amplifier (CB6984E)
Found in an American publication from the 1980s, this circuit can be found in commercial sound...
Ice Warning on the Track (CB6046E)
We found this circuit in an 80's Radio Electronics. The circuit uses a PTC sensor and an LED...