1, new 5 v relay module
2, can be used as MCU development board module, which can be used as a home appliance control
3, 5 v and 12 v TTL control signal
4, dc or ac signal control, can control 220 v ac load.
5, there is a often opened a normally closed contact
6, has a power light
7, with control indicator light, and bright, disconnect is not bright
8, triode driven increase relay coil, feet high impedance control.
9 have a drop-down circuit, control foot, to prevent the impending relay misoperation