Relay working principle and related knowledge

A relay is a generic term that means inherited control. With a small amount of power and current, driving a device (motor or electromagnet) drives a load component (such as an electric switch or contact pad) to carry the contact piece to carry a large current. For example, our switch requires only a 12V 0.1A control relay, which allows the relay to help us switch on and off millions of volts, UHV lines with currents of up to several thousand or even tens of amps. No matter where you want to avoid the danger of the controller or the device, it is best to use the relay. Let us touch the safe side and let the relay touch the dangerous side. We only need to control the relay action, the relay will help us to connect. We don't want to touch some lines in person. The relay is a general term and is also divided into contactors (specially used to control the on-off, load a large current relay, but the action is not fast) intermediate relay (relatively fast, generally long-form small is this) time relay (use To control the time action, such as the street light is automatically lit at night, there are many other many. Get a new thing with a combination of devices and relays, such as a time relay with a combination of a clock and a relay.

Relay definition

A relay is an automatic control device that changes the output when the input quantity (electricity, magnetism, sound, light, heat) reaches a certain value.

Relay characteristics of relays

The input signal x of the relay is continuously increased from zero to the action value xx when the armature starts to pull in. The output signal of the relay immediately jumps from y=0 to y=ym, that is, the normally open contact is disconnected to open. Once the contact is closed, the input x continues to increase and the output signal y will no longer change. When the input quantity x drops from a value greater than xx to xf, the relay begins to release and the normally open contact opens. We call this characteristic of the relay a relay characteristic, also called the input-output characteristic of the relay. The ratio of the release value xf to the action value xx is called the feedback coefficient, that is, the ratio of the control power Pc outputted at the contact of Kf=xf/xx to the minimum power P0 absorbed by the coil is called the control coefficient of the relay, that is, Kc=PC/P0.

The role of the relay

A relay is an electronic control device that has a control system (also called an input loop) and a controlled system (also called an output loop). It is usually used in an automatic control circuit. It actually uses a small current to control the larger. An "automatic switch" of current. Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit.