Emergency lighting fixtures are composed of several parts, including light source, light source driver, rectifier, inverter, battery pack, and sign lamp housing. Normally, 36V drives the light source to illuminate normally through the light source driver, while supplementing the battery pack with electricity through a rectifier. Even if the lighting is turned off after work, the rectifier still operates in a charged state, so that the battery pack is always in a full combat readiness state. When encountering an emergency situation and the mains power suddenly stops, the inverter will automatically start the inverter circuit, converting the low voltage energy of the battery pack into high voltage energy, and driving the light source to continue lighting.

The emergency lighting system used in China is mainly of the independent control type with its own power supply. The normal power supply is connected to the ordinary lighting power supply circuit, and it usually corresponds to the charging of the emergency light battery. When the normal power supply is cut off, the backup power supply (battery) automatically powers up. This form of emergency light has a large number of electronic components such as voltage transformation, voltage stabilization, charging, inverter, and battery inside each lamp. The battery of the emergency light needs to be charged and discharged during use, maintenance, and failure. Another type is the centralized power supply and centralized control type, where there is no independent power supply inside the emergency lighting fixtures. When the normal lighting power supply fails, it is powered by the centralized power supply system. In this form of emergency lighting system, all complex electronic circuits inside the lamps are eliminated, and emergency lighting lamps are no different from ordinary lamps. The centralized power supply system is set up in a dedicated room.