1. 5V relay module 2. It can be used as a single-chip development board module, and can be used as a home appliance control 3. 5V-12V TTL control signal 4. Control DC or AC signal, can control 220V AC load 5. There is a normally open and a normally closed contact 6. Has a power indicator 7. There is a control indicator light, which is bright when closing, but not bright when disconnecting 8. Transistor drive increases the relay coil, and the control pin is high impedance 9. The control pin has a pull-down circuit to prevent the false action of the floating relay
