| 摘要 |
A pilot light as might be used for monitoring an industrial control circuit having a normal signal circuit connectable to a control circuit element for illuminating a lamp of the pilot light when such control circuit element is operated, and also having a test circuit connectable to a test switch for testing the integrity of the lamp when the test switch is operated. A circuit for supplying current to the lamp is light coupled to both the normal signal circuit and the test circuit.
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