6 Channel 5V Opto Isolated Relay Module is a simple relay
board. 6 channel relay board works from a 5V supply to JVCC for the relays and
0V for the switching signal to relays activate. It uses a transistor to drive
the relay & optocoupler used to separate the output. Using these relay
board you can easily control high power DC 30V/AC 250V devices or appliances
using arduino or microcontroller. It can be connected directly to a
microcontroller pin. It has 3 pin terminals each relay output NO COM NC. NO
normally open with relay common pin. NC Normally connected with common.