Top positive review
32 people found this helpful
Incredible value for money.
on 27 May 2015
These are really excellent little boards containing a pair of individually switched change over relays capable of handling up to 10 Amps on the switching contacts.
There may be morre than one version out there as one review refers to both red and green LEDs however this board only has red LEDs which indicate which input is operational.
There is a 4 pin header marked GND, IN1, IN2 and VCC. Gnd and VCC are self explanatory (if not then you should really not be playing with these sort of things!). IN1 and IN2 are the input pins which control the relays 1 and 2 respectively. Connecting either of the IN pins to GND (0 volts) will cause the relay to operate and the red LED for that relay to illuminate.
There is also a header marked JD-VCC, VCC, GND. This is supplied with a jumper pre-fitted connecting JD-VCC to VCC.
DO NOT CONNECT IT BETWEEN VCC AND GND AND POWER THE BOARD UP YOU ARE LIKELY TO DESTROY SOMETHING.
I can only assume that this header intended to allow you to supply the relays from another power source instead of your Arduino, Raspberry Pi, etc etc.
This is a good idea to ensure that you do not sink too much current from the 5V rail of the device you are connected to.
I have added the schematic diagram found on the web for further information.