| 摘要 |
A circuit device of an override protection switch, including an operation unit, a rectifying/stabilizing unit, a load voltage sampling unit and a relay. The operation unit includes a comparator and a standard comparison voltage connected to the comparator. The rectifying/stabilizing unit serves to provide DC voltage for the circuit. The load voltage sampling unit has a voltage-dividing sampling section for obtaining a load sampling voltage and outputting the load sampling voltage to the comparator for the comparator to compare the load sampling voltage with the standard comparison voltage. In normal state, the relay keeps the circuit closed. The signal output terminal of the comparator is connected to the relay. With the bulb as the load, in the case that the bulb within the nominal wattage range is used and the load sampling voltage is smaller than the standard comparison voltage, the relay keeps closed to switch on the circuit. In the case that the bulb exceeding the nominal wattage is used and the load sampling voltage is higher than the standard comparison voltage, the comparator outputs a signal to the relay to cut off the circuit.
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