(20 14? The internal structure of emergency lighting installed in Dongying) school teaching building is as shown in the figure. The function of the distributor is to convert 220V AC high voltage into

(20 14? The internal structure of emergency lighting installed in Dongying) school teaching building is as shown in the figure. The function of the distributor is to convert 220V AC high voltage into 1. When the 22V lighting power supply is normal, the emergency lighting lamp will charge the battery through the charger. At this time, the electromagnet attracts the armature to form an open circuit between the bulb and the circuit where the battery is located, and the bulb does not emit light.

When the lighting power supply is suddenly cut off, the electromagnet has no magnetism, and the armature is lifted upward under the action of the spring, so that the circuit where the bulb and the battery are located forms a passage, and the battery supplies power, so that the bulb emits light and automatic emergency lighting is realized.

So the answer is: when there is electricity, the battery is charged and the light bulb does not emit light; When there is a power failure, the battery supplies power and the light bulb glows.