Photo relay XH-M131-12V

The photo relay module activates the relay at a certain light intensity. The photoresistor, which is connected with a cable 20 cm long, determines the level of illumination. When light hits the photoresistor, it changes its resistance. Because of this, the voltage in the circuit changes, which signals the amount of light. The module can be used in projects that require the relay to be triggered in the presence of a given light brightness (street lighting, turning on car headlights, etc.).

The board has an LM393 comparator that determines the light intensity across the photoresistor. The sensitivity level of the sensor can be adjusted using a trimmer resistor. The module does not have on and off timers. The relay is activated when the specified sensor sensitivity threshold is exceeded. If the illumination often changes its state, then the relay will operate frequently.

The photoresistor is connected to the module using the COS pin. There are 2 terminal blocks on the module board:

J1 (terminal 1): relay power is connected
J2 (terminal 2): load connected

There are also 2 LEDs on the board:

D1: signals the power supply of the module
D2: lights up when the specified sensor sensitivity threshold is exceeded

You can supply power to the module board from an external power source. The module supply voltage is 5 V. The relay board switches voltage up to 250 V and withstands current up to 10 A.

Module Specifications:
Chip LM393
Relay SRD-12VDC-SL-C
Maximum load 10A, 250V
Module supply voltage, V 12
Wire length, cm 20
Operating temperature, °C -25 ... +70
Module dimensions, mm 55 x 30 x 20.