What is a relay and what is a relay? What is it for?

Explanation of electromagnetic relay knowledge.

Relay is a kind of electrical control device, which is a kind of electric cooker that makes a predetermined step change in the controlled quantity in the electrical output circuit when the change of the input quantity (excitation quantity) reaches the specified requirements. Relays are usually used in automatic control circuits, and it is actually a kind of "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

Because the relay is composed of two parts, a coil and a contact group, the graphic symbol of the relay in the circuit diagram also includes two parts: a rectangular box represents the coil; A set of contact symbols represents a combination of contacts. When there are not many contacts and the circuit is relatively simple, the contact group is often drawn directly on one side of the circle, which is called centralized representation.

1. Relay is a kind of control equipment commonly used in our lives, in a popular sense, it is a switch, which is turned off or on when the conditions are met. The switching characteristics of relays are widely used in many control systems, especially discrete control systems.

On the other hand, because the electronic circuits designed for a certain purpose ultimately need to interact with some mechanical equipment, relays also play the role of interfaces between electronic equipment and mechanical equipment. Relays commonly used in control are often used for relay control, signal transmission, and isolation amplification.

In addition, there are current relays used to limit current, voltage relays used to control voltage, automotive relays, electromagnetic voltage relays, small relays, power relays, home appliance relays and so on. It is with these different types of relays that it is possible for us to control different physical quantities and complete a complete control system.

Second, the role of relays.

1. Expand the control range: for example, when the control signal of the multi-contact relay reaches a certain value, it can be changed, interrupted and connected to multiple circuits at the same time according to the different forms of the contact group.

2. Amplification: For example, sensitive relays, intermediate relays, etc., can control very high-power circuits with a very small control quantity.

3. Comprehensive signal: for example, when a plurality of control signals are input into a multi-winding relay in the specified form, the predetermined control effect is achieved after comparative synthesis.

4. Automatic, remote control and monitoring: For example, the relay on the automatic device can be combined with other electrical appliances to form a program control circuit, so as to achieve automatic operation.

Usually used in the control circuit of automation, it is actually a kind of "automatic switch" that uses a small current to control the operation of a large current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

There are many classifications of relays, and the picture below is an electromagnetic relay.

I'll tell you. Relays are indeed devices in control circuits. It is also true that a small current is used to control a large current.

But this explanation is equivalent to no explanation for you. (The score is so high, I'll make it clear to you.) Remember to give me the best) Actually, there are many kinds of relays.

I'm going to give you an example of this with a time relay. For example, we often see pressing machines in factories. The circuit inside uses a time relay.

When the switch is pressed to turn on the power supply, the relay is closed (the main structure of the relay is the copper wire wrapped in the iron. Using the principle of electromagnetic induction, the iron sheet will be magnetic, and it will adsorb the iron sheet on the other side, and then the relay will be turned on). I have already said that one end of the relay is connected to the power supply, and the other end is connected to the load (e.g. lamp, motor).

It started working as soon as the power was on. And the time relay will automatically disconnect after a certain amount of time. (There will be a mark on this relay.)

It stops working when it is disconnected. It's like pressing down on the press, and after a while, the press will stop pressing and automatically pop up. Moreover, the relay can be connected to several loads at the same time, such as the motor and the indicator light, that is to say, the motor and the indicator light are controlled by the relay at the same time.

The indicator light is on when the motor is working and turns off when it stops working. It's like the indicator light of the press-fitting machine is on when pressing, and the press-pressing stops. The lights went out.

If you have any questions, you can add them and share them with me. Thank you! )

Relay is an electronic control device, usually used in automatic control circuits, it is actually a kind of "automatic switch" that uses a smaller current to control a larger current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

Hello, the relay is a kind of safety switch, in the current load or other circumstances will trip, it has a safety switch in the middle, you can press the hope can help you!

Relay is a kind of electronic control device, it has a control system and a controlled system, usually used in automatic control circuits, it is actually a kind of "automatic switch" to control a larger current with a smaller current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.