WMYCONGCONG 2 PCS 12V 8 Channel Relay Module Optocoupler Low Level Trigger Expansion Board for Arduino UNO R3 MEGA 2560 1280 DSP ARM PIC AVR STM32 Raspberry Pi (12V 8 Channel)

hello I'm CJ windage and welcome to tinker and build today we're going to learn how to use a relay with an Arduino a relay is a device that is basically a switch that is controlled by a circuit in our case the Arduino instead of a person controlling a light switch so the main purpose of using a relay is when you want to control large voltages or current with a microprocessor like turning a light on and off we'll be using a same smart 4 channel relay module this module simplifies our life because it has the extra electronics right onboard so we can connect the relay directly to an Arduino the blue boxes are the relays and these ones are capable of switching 250 volts in 10 amps for AC or 30 volts with 10 amps for DC the black boxes at the bottom are optocouplers what they do is protect our Arduino from any stray voltages or currents that can occur with inductive loads like relays they el