Combined electric alarm clock and intruder alarm - has intruder detection switch connected in parallel with clock alarm switch to activate alarm

摘要

The electric alarm clock is combined with an intruder detection circuit, e.g. responsive to a window or door being forced open, so that the clock alarm circuit can be actuated to provide an intruder alarm. The clock alarm circuit has a buzzer or bell (1) connected directly to one terminal of the supply battery (2) and to the other terminal via two series switches (3, 4). One of these switches is a manual alarm cut-off switch (3) and the other switch (4)is actuated by the clock mechanism. The alarm switch (8) of the intruder detection circuit connected in parallel across the latter switch (4).