I intend to control an appliance that uses a triac with an Arduino. What is the best type of relay?
The difference in the choice lies not only in safety, but also in the size of the component and the type of drive. Solid state relays with optical couplers are smaller and cheaper, and more reliable. Electromechanical relays are larger but provide better insulation for loads. In addition, because they have mechanical contacts, they last less.
