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Component Knowledge Selection (13) - Relay Knowledge Special

Recently, EEWORLD has produced a collection of the essence of various component application technologies. This series of collections carefully organizes the characteristics, application circuits, selection, detection and other applications of common components such as resistors, capacitors, inductors, diodes, triodes, thyristors, field effect transistors, etc., so that everyone can start from components and master electronic circuit design step by step. Relays are automatic switching components with isolation functions. They are widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment. They are one of the most important control components.

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Internal structure of relay: Points it Requires : 1 Type:Application DocumentsUploader:雪人001Date:2013-07-04; Introduction:Internal structure of relayInternal structure of relay・Induction voltage: The critical voltage value applied to the coil to make the relay operate. The voltage required to make the relay operate is also specified in the specification. (Expressed as a percentage of the rated voltage ○%V) Because it changes with temperature, the standard temperature (20℃ or 25℃) is clearly marked in the specification. Considering the influence of the surrounding environment and the opening and closing conditions, it is also used as a guaranteed value for the initial state. ・Set voltage: The voltage required for the self-holding type relay to switch from the reset state to the set state. ・Release voltage: After the coil voltage reaches the rated voltage, the voltage is steadily reduced to restore the critical voltage value of the relay to the initial state. (The voltage required to switch from the NO contact to the NC contact) The maximum voltage index required for the relay to recover is also specified in the specification. (Expressed as ○%V of the rated voltage) ・Reset voltage: The voltage required for the self-holding type relay to switch from the set state to the reset state. ・Continuous maximum applied voltage: The maximum value of the allowable range of voltage that can be applied to the drive coil in order to prevent the performance of the relay from deteriorating. (Expressed as ○%V of the rated voltage) However, this is not a continuous allowable value. This voltage value is also affected by the ambient temperature, so the standard temperature is also indicated in the specification sheet.

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Diagram of relay and programmable controller: Points it Requires : 1 Type:Technical DocumentationUploader:sigmaDate:2018-04-26; Introduction:Graphical Relay and Programmable Controller Introduction to Graphical Relay and Programmable Controller: Programmable Controller (PLC) is a digital operation and control device based on traditional relays combined with computer technology, and is widely used. Graphical Relay and Programmable Controller is a practical introductory book written for readers who are new to relay sequence control and programmable controllers and sensor usage. Graphical Relay and Programmable Controller basically follows the steps of \"problem-circuit design-wiring-implementation\" and uses rich examples to explain the relevant content in an easy-to-understand manner. The content involves the basic knowledge of sequence control, the foundation and application of relay sequence control, the basic knowledge of programmable controllers, the instructions and basic circuits of programmable controllers, and the application circuits of programmable controllers, etc., and practice questions are given after each chapter, and the corresponding answers are given at the end.

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6. Essential Basic Knowledge Handbook for Electronic Engineers (VI): Relays: Points it Requires : 1 Type:Application DocumentsUploader:chen8710Date:2013-05-11; Introduction:6. Essential Basic Knowledge Handbook for Electronic Engineers (VI): Relays

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Relay drive circuit and relay selection guide: Points it Requires : 1 Type:Application DocumentsUploader:lamasDate:2013-09-17; Introduction:Relay drive circuit and relay selection guide 1. To ensure the normal operation of the relay, the rated voltage must be applied to the relay. 2. DC coil input voltage: To ensure the stable operation of the relay, the full DC voltage must be applied to the coil. If the power supply used has a pulsating voltage, the pulsation coefficient must be controlled within 5%. When the power supply is provided by a rectifier circuit, the relay operating characteristics (such as: starting voltage and release voltage) depend on the pulsation coefficient. Insert a filter capacitor as shown in the figure below to obtain the required operating characteristics.

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Relay terminology explanation and usage guide pdf: Points it Requires : 1 Type:Application DocumentsUploader:zczcDate:2012-12-12; Introduction:A relay is a component whose one or more outputs produce a predetermined jump when the input reaches a specified condition. For electromagnetic relays, solid-state relays and combined relays, it can be simply understood as: a switch that connects and disconnects the quilt control circuit when a specified electrical signal is applied to the input end. Precautions for the use of relays: In order to use the relay correctly, while selecting the relay and understanding its characteristics, you also need to understand some precautions for use to ensure the reliable operation of the relay. 1. The use of the relay should be as consistent as possible with the various parameter ranges listed in the product manual. 2. The rated load and life are reference values, which will vary greatly depending on different environmental factors, load properties and types. Therefore, it is best to confirm them in actual or simulated actual use. 3. DC relays should be controlled with rectangular waves as much as possible, and AC relays should be controlled with sine waves as much as possible. 4. In order to maintain the performance of the relay, please be careful not to drop the relay or subject it to strong impact. It is recommended not to use the relay after it has been dropped. 5. Relays should be used in an environment with normal temperature and humidity, less dust and harmful gases. Harmful gases include gases containing sulfur, silicon, nitrogen oxides, etc. 6. For magnetic latching relays, they should be placed in the action or reset position as needed before use. When applying voltage to the coil, pay attention to the polarity and pulse width. 7. For polarized relays, please pay attention to the polarity of the coil voltage.

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Relay Selection Manual-378 pages-9.7M.rar: Points it Requires : 1 Type:Application DocumentsUploader:frogluckyDate:2014-03-05; Introduction:Album category----Component sample album Relay selection manual-378 pages-9.7M.rar

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Universal relay wiring diagram: Points it Requires : 1 Type:Application DocumentsUploader:天河12345Date:2014-01-14; Introduction:Universal relay wiring diagram, rich resource

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Relay drive circuit principles and precautions: Points it Requires : 1 Type:Application DocumentsUploader:雪人001Date:2013-08-20; Introduction:Relay drive circuit principle and precautions According to the input and output characteristics of the integrated circuit driver 2003, some people call it \"driver\", \"inverter\", \"amplifier\", etc. The commonly used model is: TD62003AP. When the input end of 2003 is high level, the corresponding output port outputs low level, the relay coil is energized, and the relay contacts are closed; when the input end of 2003 is low level, the relay coil is de-energized and the relay contacts are disconnected; a diode that plays a reverse freewheeling role is integrated inside 2003, so it can be used directly to drive the relay.

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Switch and relay selection: Points it Requires : 1 Type:Application DocumentsUploader:电子爱好者IKDate:2013-09-21; Introduction:Selection of switches and relays 1.4.1 Switches 1. Examples of commonly used manual switches A switch is a device used to connect or disconnect a circuit. There are many types. Here we introduce manual switches. Several commonly used manual switches and their uses are shown in Table 1-18. The switch has actuated contacts (often called poles or knives) and fixed contacts (often called positions or throws). The circuit symbols of the switch are shown in Table 1-19. 2. Main parameters of the switch Rated voltage: The maximum voltage that the switch can withstand in normal working conditions. For AC power supply, it refers to the effective value of AC voltage. Rated current: The last large current allowed to flow through the switch during normal operation. In AC circuits, it refers to the effective value of AC current. In addition, there are parameters such as contact resistance, insulation resistance, withstand voltage, and life. 3. Switch detection (1) Mechanical switches are firstly to check the appearance for damage; secondly, to check whether the mechanical action of the switch is flexible; thirdly, to use a multimeter to measure the resistance value when the switch is connected and disconnected. The resistance value is 0 when connected. If the resistance value is too large, it means that the contacts are corroded or the contact is poor. ⑵ Membrane switch and conductive rubber switch First check the appearance of the rubber for damage, then test whether the contact can be connected. Under normal circumstances, the contact resistance value is 0 when the switch is pressed. If the contact resistance is large, the contact should be cleaned. After cleaning, the effect is not obvious and it can no longer be used. In addition to the above switches, there are also photoelectric switches, which are composed of light-emitting diodes and receiving tubes. Table 1-18 Common manual switches and their uses ⑶ Selection of relays The main parameters of relays are divided into signal parameters and control parameters. For electromagnetic relays, pay attention to the rated working voltage of the coil, which is generally available from 3 volts to 48 volts. The control parameter is mainly the contact load capacity, which is generally between 2A and 10A. Select the appropriate relay based on the size of the two. Solid relays are photoelectrically isolated. When selecting, first pay attention to whether the controlled signal is DC or AC, then the input signal voltage (generally a few volts to tens of volts), the relay control voltage and current size (load capacity). In addition, pay attention to the size of the relay. 1.4.2 Relay 1. Relay appearance and symbol Relay is an electrical control switch that can control a larger current with a smaller current and is widely used in control circuits. There are many types of relays. They can be divided into electromechanical relays and solid relays in terms of composition, DC and AC relays in terms of control current, and heat, temperature, light, time relays, etc. in terms of control parameters. In recent years, solid relays developed from electronic components are replacing electromechanical relays in many occasions. The appearance of commonly used relays is shown in Figure 1-37. The symbol of the relay is shown in Figure 1-38. 2. Detection and selection of relays ⑴ Detection of electromagnetic relays ① Measure the DC resistance of the coil. According to the nominal DC resistance of the relay, use a multimeter to measure whether the DC resistance value of the coil is consistent with the nominal DC resistance. ② Measure the contact resistance of the contact. The contacts are divided into move-close (normally open) and move-break (normally closed) contacts. Both types of contacts should have a contact resistance of 0 when closed and an infinite resistance when disconnected. ⑵ Detection of solid relays DC solid relays are generally marked with \"+\" and \"-\" signs at the input and output ends, and are annotated with the words \"DC input\" and \"DC output\". When using a multimeter to test, select the R×10K range and measure the forward and reverse resistance values of the four pins respectively. Since the input end is internally connected to a light-emitting diode, under normal circumstances, the measured primary resistance is small and the secondary resistance is large. The output end should have infinite forward and reverse resistance. The internal circuit of the output end should be tested with a test circuit.

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Lighting Relay Quick Guide: Points it Requires : 1 Type:Application DocumentsUploader:sigmaDate:2018-05-17; Introduction:Lighting Relays Quick Guide Lighting Relays Quick Guide

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New Contactor and Relay Practical Manual 481 pages 22.57M.pdf: Points it Requires : 1 Type:Application DocumentsUploader:tywDate:2013-08-22; Introduction:New Contactor and Relay Practical Manual 481 pages 22.57M.pdf

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Modern Control Relay Practical Technical Manual: Points it Requires : 1 Type:Application DocumentsUploader:tywDate:2013-12-10; Introduction:Modern Control Relay Practical Technical Manual

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Relay drive circuit: Points it Requires : 1 Type:Application DocumentsUploader:雪人001Date:2013-05-18; Introduction:Relay drive circuit Relay drive circuit

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Principle and structure of common relays: Points it Requires : 1 Type:Application DocumentsUploader:jujuyaya222Date:2013-09-19; Introduction:Principle and structure of common relays: In daily life, students must be familiar with the relay itself, but they may still be unfamiliar with its working principle and structure. This article will briefly explain the principle and structure of electromagnetic relays so that everyone can have a better understanding and avoid safety accidents caused by relays. In addition, this article will briefly explain a variety of relays. Keywords: relay electromagnetic relay principle 1. Definition of relay A relay is an automatic control device that changes the output in a jump-like manner when the input quantity (electricity, magnetism, sound, light, heat) reaches a certain value. 2. Relay characteristics of relays When the input signal x of the relay increases continuously from zero to the action value xx when the armature begins to attract, the output signal of the relay immediately jumps from y=0 to y=ym, that is, the normally open contact changes from off to on. Once the contact is closed, the input quantity 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 is disconnected. We call this characteristic of the relay a relay characteristic, also known as the input-output characteristic of the relay.

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Relay Classification and Low Current Relays: Points it Requires : 1 Type:Application DocumentsUploader:nonogugu66Date:2013-09-18; Introduction:Relay Classification and Low Current Relays

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Analysis of the causes of unstable relay operation: Points it Requires : 1 Type:Application DocumentsUploader:雪人001Date:2013-09-16; Introduction:Analysis of the causes of unstable relay operation

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Identification and testing of switches, connectors and relays: Points it Requires : 1 Type:Application DocumentsUploader:solarelecDate:2013-09-18; Introduction: Identification and testing of switches, connectors and relays

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