| 摘要 |
<p>DANIEL HERBERT WOLF ANTI-THEFT PURSE ALARM The alarm includes a movement sensitive trigger mechanism and electronic circuitry responsive to the trigger and adopted to generate an alarm signal when actuated thereby. The trigger mechanism is an electronic switch comprised of an LED and a photosensitive transistor. The active surfaces of the devices are normally aligned, the LED being suspended by a wire from a support above the transistor. Vibration or movement above a given magnitude results in misalignment of the active surfaces which causes the transistor to generate a trigger signal. The sensitivity of the electronic switch is adjustable by varying the spacing between the active surfaces. A delay circuit is interposed between the electronic switch and the remainder of the alarm circuitry such that generation of the alarm signal is prevented for a preset time interval after the arming of the device in order to permit the electronic switch to achieve mechanical equilibrium.</p> |
