NOTE: This solid state relay works great directly with Arduinos and Raspberry PI.
This solid state relay (SSR) allows you to control high-curent DC loads from lower voltage DC control circuitry. Solid state relays have several advantages over mechanical relays. One such advantage is that they can be switched by a much lower voltage and at a much lower current than most mechanical relays. Also, because there’s no moving contacts, solid state relays can be switched much faster and for much longer periods without wearing out.
This particular SSR can switch current loads of up to 40 Adc with a 3-32V DC input. Each one of these relays is equipped with four screw terminals (for use with ring or fork connectors).