Many times we need to drive loads in alternating current from our microcontroller, however, we are afraid to do so since we know that working with alternating current at high voltage is quite dangerous.

 This card already has 2 relays included, in addition each relay has its own opto isolator, which protects our circuit from any accident that happens on the high voltage side.

 It only requires 5V to work and the connection to 2 pins of the microcontroller to drive both relays.