This module is a high-level trigger, requiring a trigger current of no less than 5mA. Some single-chip IO ports (like the 51) have low output capacity and may need a pull-up resistor or increased circuit drive capacity. High-level driving offers the advantage of disconnecting the control line, ensuring high safety when charging is not in operation. 12V Relay Can be used as a single-chip development board module or for home automation. Controls DC or AC signals, capable of controlling 220V AC loads. Features normally open and normally closed contacts. Includes a 'power' indicator light. A control indicator shows when the relay is activated (on) or deactivated (off). Transistor-driven to boost the relay coil, featuring a high-impedance control foot. The control circuit includes a booster to prevent malfunction in the suspension relay. High quality, color (black, yellow) random delivery. The blue terminal is designed for easy wiring. Circuit board size: 46mm X 46mm, height 20mm. Positioning hole size: 40mm x 40mm. Material: Metal Color: RED Package Contents: 1x Relay Module Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowable measurement error is +/- 1-3 cm.