For alternating current, the armature is made of electrotechnical steel to reduce losses. In the first case, the device can be neutral or polarized. The control current can be either direct or alternating.The relay is designed to regulate voltages and currents, be used as a storage or conversion device, and record deviations of typical values’ parameters. Control voltage sources can be sensors (pressure, temperature, etc.), electrical circuits and other devices that supply low current or low voltage.Įlectromagnetic relay is used in automation circuits when controlling various technological installations, electric drives and other devices. When the voltage is cut, the armature returns to the initial position. When the control signal is given, the magnet starts to attract the armature and close or open the circuit. The spring holds the armature at its original state. The relay operates due to the electromagnetic force in the cores when the current is applied to the coil coils. Some models may have additional electronic components built-in: a resistor for more accurate relay operation, a capacitor to reduce interference, a diode to eliminate overvoltages. The anchor is a plate made of magnetic material. An electromagnet is a wire that is wound on a ferromagnetic coil. It consists of an electromagnet, a moving armature and a switch.
Electromagnetic and Solid-state Relays Electromagnetic RelaysĪn electromagnetic relay is an electrical device that mechanically closes or opens a load circuit using a magnet. The following parameters characterize the relay:ĭepending on the type of these internal disconnecting mechanisms and the device’s features, two main relay groups can be distinguished: electromechanical relays (switching by electromagnet) and solid-state relays (switching by special semiconductor components). The relay can be imagined as a remote control, with which we perform the necessary actions using relatively “weak” signals. The Arduino sends a signal, while the very closing or opening of the “powerful” circuit will relay special internal mechanisms. With the help of an Arduino and a relay, we control the process of switching on or off in the same way as we switch on or off the light in the house – by giving the command to short or open. In its turn, the foot mechanically closes the load contacts. There is a field in the coil, which attracts a metal foot.
Supply voltage to the electromagnetic coil. The working principle of the relay is as follows. 3.7 Example of a Sketch Working Principle of Relay