Specifications:

1. Can be used as microcontroller development board module can be used as home appliance control
2. 5 V-12V to TTL control signal
3. The control signal DC or AC, 220V AC load can be controlled.
4. There is a normally open and one normally closed contact
5. A power indicator light
6. A control indicator, pull off, disconnect does not shine
7. Transistor drive to increase the relay coil control pins high impedance.
8. The control pin has a pull-down circuit to prevent malfunction relay vacant.