An electromechanical relay uses a physical moving part to connect contacts within the output component of the relay. The movement of this contact is generated using electromagnetic forces from the low-power input signal, allowing the completion of the circuit that contains the high-power signal. A PCB relay is a smaller relay that can mount directly to a PCB. These relays tend to have high voltage ratings and may mount to a board as through-hole components due to their size and weight. A relay is used whenever there is a need to control a high voltage circuit with a second low power circuit.
The electromagnetic PCB relay works by applying an electromagnetic field when power gets applied to the coil, subsequently causing the movement of the armature and making the contacts either close or open. PCB relays get classified by construction, mounting type, or function. Electromechanical relays are available in both latching and non-latching varieties. Non latching relays require continuous current flow through the coil to keep the relay actuated. These are often used in applications where the relay must switch back to a safe state in the event of a power failure.
The typical applications of electromechanical relays include motor control, automotive applications such as an electrical fuel pump, industrial applications where control of high voltages and currents is intended, controlling large power loads, and so on. Relays are the essential component for protection & switching of a number of the control circuits & other electrical components.
