SPDT Mini Toggle Switch (On/Off/On)

This Relay Shield from Evil Mad Scientist is a simple Arduino add-on that gives your Arduino the ability to control a single electromechanical relay for switching loads of up to 24VDC or 40VAC. Each Relay Shield comes equipped with a single pole – double throw (SPDT) sealed relay which can handle a current load of up to 5A. This means that when current is applied to the coil it throws a simple changeover switch, terminating the connection from the NC (Normally Closed) contact to ground and closing the NO (Normally Open) contact. Use them to switch high voltage/high current devices. As this is a shield, it is powered straight from the 5V power supplied by your Arduino, simply slide it into your Arduino or shield-compatible board (like the RedBoard) and you will be good to go!

This 4 Channel Relay Shield is an easy way to control high voltage applications with the Arduino. The maximum switching power for each relay is 70W. You can directly control this shield with the Arduino digital I/Os with an external 9V DC supplty.