This circuit is for a siren that can be used with any of the above alarms and also other types. The circuit is from a Radio Electronics magazine from May 1975.
This fully isolated control circuit provides an output signal by triggering a 130 mA relay when...
The capacitor used in this circuit can have values between 5 and 30 uF. The circuit is of old...
We found this circuit in an old Argentine publication. The transistor can be replaced by a more...