Solid state relays or semiconductor relays (also called SSRs) are semiconductor devices that can be used in place of mechanical relays to switch electricity to a load in many applications. They are purely electronic devices, normally composed of a low current control side and a high current load side (switching side). Many solid state relays feature electrical isolation in the thousands of volts between the control side and the load side. This is usually achieved through optical isolation using an optoelectronic device (a photocoupler). [Read more…]