We found this simple alarm that uses a double contact relay to obtain the lock when triggered. The circuit can also control an external load like a power siren. The circuit is from English documentation from 1980. The transistor may be the BC548.
We found this simple alarm that uses a double contact relay to obtain the lock when triggered. The circuit can also control an external load like a power siren. The circuit is from English documentation from 1980. The transistor may be the BC548.