Relay principle (various relay principles)

Speaking of relay, you may not be familiar with it. It is based on the principle of electromagnetic electrification. When working, the electromagnet is energized and sucked by the armature, so that the working circuit is closed, the magnet is de-energized and demagnetized, and the circuit is cut off, which can play a very good role in protecting the safety of electricity use. In fact, the principle of relay is very simple, but how much do you know about the whole content of relay working principle? Today, Bian Xiao will explain the principle of relay race. What are its classifications? If a friend wants to know this knowledge, please refer to Bian Xiao's explanation.

Working principle of relay

When the relay works, the electromagnet is energized, the armature is sucked down to make D and E contact, and the working circuit is closed. When the electromagnet loses its magnetism when it is cut off, the spring pulls the armature up and cuts off the working circuit. Therefore, the relay is a switch that uses an electromagnet to control the on-off of the working circuit.

Advantages of using relay control circuit: controlling high voltage with low voltage; Remote control; Automatic control.

Relay is an automatic electrical switch that works by electromagnetic induction.

Working principle of 1. relay

Relay is an electronic control device, which has a control system (also called input loop) and a controlled system (also called output loop). Usually used in automatic control circuits, it is actually an "automatic switch" that controls a larger current with a smaller current. Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit.

Electromagnetic relay generally consists of iron core, coil, armature and contact reed. As long as a certain voltage is applied to both ends of the coil, a certain current will flow in the coil, thus generating an electromagnetic effect. Under the attraction of electromagnetic force, the armature overcomes the pulling force of the return spring and attracts the iron core, thus driving the moving contact of the armature to attract the stationary contact (normally open contact). When the coil is disconnected, the electromagnetic attraction disappears, and the armature will return to its original position under the reaction of the spring, so that the moving contact and the original static contact (normally closed contact) attract each other. In this way, it is attracted and released, so as to achieve the purpose of making and breaking the circuit. For the normally open contacts and normally closed contacts of relays, we can distinguish them as follows: the static contacts that are in the off state when the relay coil is not energized are called normally open contacts; Static contacts in the on state are called "normally closed contacts".

Principle of hot reed relay

Thermal reed relay is a new type of thermal switch which uses thermomagnetic materials to detect and control temperature. It consists of a temperature-sensing magnetic ring, a constant magnetic ring, a reed switch, a heat-conducting mounting piece, a plastic substrate and other accessories. The hot spring relay does not need coil excitation, but the magnetic force generated by the constant magnetic ring drives the switch to act. Whether the constant magnetic ring can provide magnetic force to the reed switch is determined by the temperature control characteristics of the temperature sensing magnetic ring.

Working principle of solid state relay (SSR)

Solid-state relay is a four-terminal device, two of which are input terminals, the other two are output terminals, and an isolation device is used in the middle to realize the electrical isolation of input and output.

According to the type of load power supply, solid state relays can be divided into AC type and DC type. According to the switch type, it can be divided into normally open type and normally closed type. According to the isolation type, it can be divided into hybrid type, transformer isolation type and photoelectric isolation type, with photoelectric isolation type being the most.

Through the introduction of relay principle, we can see that there are many kinds of relays, and the working principles of different kinds of relays are relatively different. The advantage of using relay is that in the circuit control system, an automatic electrical switch can control high voltage with low voltage and work by electromagnetic induction. For example, solid-state relay is mainly divided into AC type and DC type, and it can also be divided into normally open type and normally closed type according to the switch. Therefore, in order to truly master the principle of relay, we must first start with it.