| 摘要 |
An electronic guard strip proximity switch for prevention of collision with a moving object, controls a control means such as a relay (7), and comprises at least one antenna (1) forming a capacitor together with a base (2) in its ambience, a voltage source such as a generator (3) from which an alternating voltage is conducted to said antenna, and an amplifier (4) to which the control means and the antenna are connected so that the change of voltage arising from any capacitive perturbation in the antenna is conducted to the control means (7). The voltage from the amplifier (4) is conducted over a rectifier (11) to an amplifier (5) which is so connected that its direct current gain is +1, but which amplifies any change of voltage occurring in the d.c. voltage input to a multiple and which further controls through a comparator (6) the control means (7). The guard strip may be mounted on the edge of lift doors. <IMAGE> |
