It is installed on the instrument panel in the cab, and the quantity depends on the design. It is used to indicate the technical conditions of relevant lighting, light signals and working systems, and send out alarm light signals for abnormal conditions. Indicating lamps using incandescent lamps as light sources are composed of lamp caps, bulbs, lampshades, connecting wires, etc. Some lamps using light-emitting diodes as indicating lamps are generally installed on the panels of panels, panels, desks and cabinets of high and low voltage power distribution devices, panels of some low-voltage electrical equipment and instruments, or other conspicuous positions. The indicator light reflecting the working state of the equipment is usually red to indicate that it is in the running state, green to indicate that it is in the shutdown state, and milky white to indicate that it is in the test state; The indicator light reflecting the position status of the equipment usually indicates that the equipment is energized when the light is on, and that the equipment is de energized when the light is off; The indicator light reflecting the working state of the circuit. Generally, the red light indicates electrification, and the green light indicates no power. To avoid misjudgment, check the integrity of the bulb or LED regularly or regularly during operation.