The Role of the Relay and Its Working Principle

Introduction

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.

Article Core	Relay Function and Working Principle
Purpose	Introduce what relay function and working principle are.
Application	Semiconductor industry.
Keywords	Relay

Catalog

Introduction
Relay Definition	Component Symbol
	Electrical Symbol and Contact Form
	Contact Form
The Role of the Relay	The Role of the Intermediate Relay
	Use of Intermediate Relay	1,Instead of Small Contactors
		2, Increase the Number of Contacts
		3, Increase the Contact Capacity
		4,Conversion Contact Type
		5,Conversion Contact Type
		6, The Conversion Voltage
		7,Eliminate Interference In the Circuit
Working Principle of Relay
Relay Classification	1,Classified According to the Working Principle or Structural Characteristics of the Relay
	2, Classified According to the Size of the Relay
	3, Classified According to the Load Classification of the Relay
	4, Classified According to the Protective Characteristics of the Relay
	5, Classified According to the Principle of Relay Action
	6. Classified According to the Physical Quantities of Reactions
	7. Classified According to the Role of Relay in Protection Circuit
Relay Detection	Test instruction
	Testing Process
	Precautions

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.

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.

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.

Component Symbol

Since the relay is composed of two parts: the coil and the contact group, the graphical symbol of the relay in the circuit diagram also includes two parts: one long square indicates the coil; and one set of contact symbols indicates the contact combination. When the contactless circuit is relatively simple, the contact group is often drawn directly on one side of the coil frame. This drawing is called a centralized representation.

Electrical Symbol and Contact Form

The relay coil is indicated by a long square symbol in the circuit. If the relay has two coils, draw two long square boxes. At the same time, the relay symbol "J" is marked in the long box or next to the long box. There are two ways to represent the contacts of a relay: one is to draw them directly on the long square side, which is more intuitive. The other is to draw the respective contacts into their respective control circuits according to the needs of the circuit connection. Usually, the same text symbols are marked on the contacts and coils of the same relay, and the contact groups are numbered. To show the difference.

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