Title: Alarm installation with a number of self powered indicating elements

• Summary
• Claims
• Description
• View all

Abstract: An alarm system includes a number of self powered indicating elements each with an integral warning device. Each indicating element includes a control circuit which may comprise a transistor switching circuit, transistor oscillator or part of a wheatstone bridge circuit for example. Each of these control circuits is connected via two lines to a common control element at a position remote from the remainder of the control circuit, such element comprising for example a resistor, a battery or a zener diode dependent on the type of control circuit utilized. A switch is also included to provide, on actuation, either a short circuit or open circuit condition between the two lines. Actuation of this switch or tampering with the lines so as to cause a short circuit or open circuit condition to occur will result in operation of the alarm.


Do you think this is a good invention? Vote now: