This circuit was found in Mullard's transistor application manual from 1960. More modern transistors can be used. The zener diodes used have the indicated voltages.
The TBA810 integrated circuit is no longer common today. This circuit shows an application of this...
The resistor Re determines the current in the LED and can be changed. The circuit is from a 1978...
This circuit causes the room light to go on when the alarm goes off. The circuit is from 2003...