| 摘要 |
A resettable, latching indicator is described. The indicator has a pair of electrical terminals through which it connects to the circuitry whose state is being indicated. The device includes an electromagnetic coil with a first lead connected to a first terminal of the device and a second lead connected to a first contact within the device. A second contact within the device is connected to the second indicator terminal, completing the circuit within the device. In a preferred embodiment, the device is arranged as a fuse state indicator with the device terminals connected in parallel with a fuse. Before fuse blow, an internal electrical contact is formed as the first and second contacts are closed an abutment formed on a spring-biased indicator flag. When the fuse blows, current passes through the coil, thus creating a magnetic field. The field moves a spring-biased armature having a catch which normally retains the indicator flag in a non-indicating position. When the armature is moved, the catch releases the flag. The energy stored in the flag's spring is thereby released and the flag moves from a first, non-indicating position to a second, indicating position. Upon moving to the non-indicating position, the flag's abutment no longer keeps the contact members closed. This cuts off all current to the coil after fuse blow.
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