Touch control alarm system - has reduced current consumption during pre-alarm state by using multivibrator

摘要

The touch control alarm system is operated by hand on a touch plate (7). A thyristor (A7) has its trigger connected to the touch plate. This 'trigger' thyristor actuates the discharge of a capacitor (55) charged by a rectified alternating current. This current is delivered by a DC current-AC current converter so as to operate an opto-electronic relay (55) in series with the capacitor. The current also drives into operation a amplifier thyristor which is in series with an alarm (60) or timed relay designed to switch on the alarm. A multi-vibrator precedes the converter so as to make it operate intermittently. The converter supplies the circuit consisting of the opto-electronic relay (55) and the 'trigger' thyristor. An alarm of alarm of this type can also be supplied with direct current obtained by rectifying the mains supply. The rectified alternating current necessary for operation of the opto-electronic relay (55) also being obtained from the mains supply.