Indicator light refers to a device that uses light to monitor the working or position status of circuits and electrical equipment. Indicator lights are commonly used to reflect the working state of a circuit (with or without power), the working state of electrical equipment (operation, shutdown, or test), and the position state (closed or open).

Working principles:

There are two main types of indicator devices used in indicator circuits: light emitting diode indicator devices and small electric beads.

(1) Principle of LED indicating device

(2) Principle of electric ball indicator light

The circuit of the bead indicator light is very simple, usually powered by an AC power source. A group of secondary coils of the power transformer directly supplies power to the small beads, sometimes several small beads are connected in parallel as indicator lights. The disadvantages of small beads are high power consumption and large volume. This indicator circuit is commonly used to indicate a power source.

Application:

In various electronic appliances, many of them use indicator lights to indicate the operation and working status of the machine.

An indicator light that reflects the working status of the device. Generally, a red light indicates that it is in the working state, a green light indicates that it is in the shutdown state, and an ivory light indicates that it is in the test state;

An indicator light that reflects the location and status of the device. Generally, when the light is on, it indicates that the device is charging, and when the light is off, it indicates that the device is out of power;

An indicator light that reflects the working status of a circuit. Generally, a red light indicates that it is charged, and a green light indicates that it is not powered.

Classification:

There are two main types of indicator devices used in indicator circuits.

(1) LED indicating device. Light emitting diodes (LEDs) are used as indicating devices (indicators), which have the characteristics of small size, low power consumption, eye-catching indications, and many color changes. The indicator lights in the combination audio system are mostly light emitting diodes.

(2) Small electric beads. Small electric beads are generally used only for tuning scale indication, and sometimes for power indication. The indicator can be powered by either AC or DC power.