Varistor perfect surge limiter

What is a Varistor

A Varistor is a nonlinear resistor primarily composed of zinc oxide, used as a metal oxide semiconductor component,primarily used for surge protection in circuits. Varistors are classified into symmetric (non-polarity) and asymmetric (with polarity) types based on their voltage-ampere characteristics. This metal oxide varistor is highly sensitive to voltage; when a set voltage level is reached, the varistor's resistance conducts rapidly.

Due to characteristics of high effective nonlinear coefficient,large through-flow capacity,fast action and no continued flow, varistors are widely used for lightning surge protection and surge protector of electronic equipments,which could absorb various operating surge & lightning wave voltages effectively, protecting circuits from interference and damage.

Varistor Application

Varistors are extensively used in surge protection across various electronic engineering fields. Common applications include:

1. 1.Telecommunications Surge Protection : Varistor protects telecom equipment from voltage spikes.
2. 2.MOV Surge Protection for Electricity:  Metal oxide varistor ensures the safety of electrical systems.
3. 3.MOV for Surge Protection of Consumer Electronics: Used in devices like telephones,converter,power meter, power distribution cabinets, socket box, distribution box, power switch, voltage regulator, and more to prevent surge current damage.
4. 4.Lightning surge protection: Enhancing the durability and performance of lighting solutions such as LED Lighting, power lightning protection box,lightning arrester (SPD surge protection special) etc.

5. 5.Surge Limiter for Automotive Applications：Varistors safeguard automotive electronics by protecting sensitive circuits from electrical transients, ensuring the reliability of control units and communication lines.

   6.Power Supplies Surge Protection: protects power supply circuits from surges, ensuring reliable system operation.

6. 7.Industrial Equipments: Varistors safeguard industrial motors, drives, and control systems from voltage transients, ensuring efficiency and safety.

7. 8.Data Line Surge Protection: Metal-oxide varistor protects communication data lines from voltage surges, ensuring reliable transmission and safeguarding sensitive components.

8. 9.Power Factor Correction Circuits: Varistors stabilize voltage and protect against transients in power factor correction, enhancing electrical system efficiency.

Application Examples

Examples of varistor applications include surge protection in motor and protected circuit:

 

 

Advantages of Varistors

1. Varistor offers numerous benefits, making them essential components in electronic circuits:

   1. 1.Wide Voltage Range: Suitable for various voltage levels, ensuring broad applicability.
   2. 2.High Energy Tolerance: Capable of handling significant energy surges, protecting sensitive equipment.
   3. 3.High Nonlinear Coefficient: Provides effective surge suppression, safeguarding devices from voltage spikes.
   4. 4.Low Leakage Current: Ensures minimal power loss, enhancing energy efficiency.
   5. 5.Symmetrical V-I Characteristics: Delivers stable performance under varying electrical conditions.
   6. 
   7. 6.Low Residual Voltage: Minimizes the voltage remaining after a surge, reducing potential damage.
   8. 7.Fast Response Time: Reacts immediately to voltage spikes, offering timely protection.
   9. 8.No Continued Flow: Prevents unwanted current post-surge, protecting circuit integrity.
   10. 9.Excellent Voltage Ratio: Maintains stable operation across different voltage levels.
   11. 10.Strong Surge Protection: Effectively safeguards circuits from high-energy surges, extending device longevity.
   12. 11.Stable Voltage Suppression: Consistently inhibits voltage spikes, ensuring reliable protection.
   13. 12.High-Quality Materials: Crafted from superior materials for durability and performance.
   14. 13.Reliable Operation: Ensures long service life and dependable functionality.
   15. 14.Wide Application: Suitable for a wide range of industries and devices, enhancing overall utility.

   Optimize your circuit protection with varistors that deliver performance, reliability, and versatility.

Varistor Key Features

Varistor Symbol

The standard varistor symbol in circuit diagrams is as below:

• Rectangle: Represents the resistor.
• Diagonal Line: Crosses the rectangle, indicating its function.
• Parallel Line Segment: Signifies the varistor's non-linear behavior.

This symbol is universally recognized in electrical schematics, ensuring quick identification by engineers and technicians working with electronic components.

Metal Oxide Varistor Main Specifications

Item	Parameter	Specification
1	Varistor Voltage	18~1800V
2	Max. Allowable Voltage (AC/DC)	10~1000V (AC) / 14~ 1465V (DC)
3	Max Varistor Clamping Voltage	38-~ 2970V
4	Energy 10/1000µS	0.4- ~ 2500 J
5	Withstanding Surge Current 8/20µS	50-70000 A
6	Rated Power	0.01-1.20 W

Metal-Oxide Varistor Dimensions

Varistors come in various sizes depending on the specific series. Detailed dimension specifications can be provided based on the selected model.

Varistor Selection

Choosing the right Metal Oxide Varistor depends on your application’s voltage and energy requirements. Consider factors such as varistor voltage, maximum allowable voltage, and energy capacity when selecting the appropriate varistor.Main factors to consider include:

- Voltage rating.

- Current rating.

- Size and form factor.

- Varistor clamping voltage. 

- Energy absorption capability.

- Reliability and lifetime requirements.

Varistor Working Principle

The working principle of a varistor is based on the nonlinear voltage-current characteristics of the material.When varistor in a rest state, relative to the protected electronic components, has a very high impedance (number megohm) without changing circuit characteristics of the original design.

When achieve the momentary surge voltage (more than breakdown voltage of the varistor), the varistor impedance will be low (only a few ohms.) and caused the original short circuit.In other words, electronic products or components are thus protected.

Metal Oxide Varistor Naming Rules

Varistors typically follow a naming convention that includes information about their voltage rating, size, and other specifications.

Details are as below:

1. Metal Oxide Varistor Model List

Here is a main mov varistor datasheet:

Item	Varistor Series	Varistor Element Diameter	Varistor Voltage	Max Allowable Voltage		Max Varistor Clamping Voltage	Energy 10/1000µS (J)		Datasheet
		(mm)	(V)	(AC)	(DC)	(V)	N(Standard) Series	J(High Surge& High Energy) Series
1	05D	5mm	18 ~ 750	10 ~ 460V	14 ~ 615V	38 ~ 1240V	0.4 ~ 22.4	0.6~32	05D Series Varistor datasheet
2	07D	7mm	18 ~ 820	10 ~ 510V	14 ~ 670V	38 ~ 1355V	1.0 ~ 69.2	3~104	07D Series Metal oxide varistor
3	10D	10mm	18 ~ 1100	10 ~ 680V	14 ~ 895V	38 ~ 1815V	2.8 ~ 133	3~155	10D Series Metal-oxide varistor
4	14D	14mm	18 ~ 1800	10 ~ 1000V	14 ~ 1465V	38 ~ 2970V	6.6 ~ 336	7.0~510	14D Series MOV varistor
5	18D	18mm	18 ~ 1100	10 ~ 680V	14 ~ 895V	38 ~ 1815V	7.2 ~ 252	11~495	18D Series MOV surge protector
6	20D	20mm	18 ~ 1800	10 ~ 1000V	14 ~ 1465V	38 ~ 2970V	6.1 ~ 560	13~860	20D Series surge suppressor varistor
7	25D	25mm	18 ~ 1600	10 ~ 1000V	14 ~ 1280V	38 ~ 2640V	13 ~ 805	20~970	25D Series mov metal oxide varistor
8	32D	32mm	33 ~ 1600	20 ~ 1000V	26 ~ 1280V	65 ~ 2640V		40~1080	32D Series mov surge suppressor
9	40D	40mm	200 ~ 1600	130 ~ 1000V	170 ~ 1280V	330 ~ 2640V		40 ~ 1080	40D Series zinc oxide varistor
10	53D	53mm	200 ~ 1600	130 ~ 1000V	170 ~ 1280V	330 ~ 2640V		550 ~ 2500	53D Series disk varistor
11	34S	34x34mm Square	200 ~ 1600	130 ~ 1000V	170 ~ 1280V	330 ~ 2400V		330 ~ 1500	34S Series mov for surge protection

Packing Specification of Varistors:

Varistor User Feedback and Summary

User Feedback of Varistors

Customers consistently praise Varistors for their reliability, fast response, and excellent surge protection capabilities. They are widely regarded as essential components for protecting sensitive electronic equipment from voltage spikes and surges.

Varistor Summary

Varistors, particularly metal oxide varistors (MOV), are essential for protecting electronic circuits from voltage surges and transients. With their fast response time, high energy tolerance, and reliable performance, MOV varistors safeguard a wide range of devices, including consumer electronics, telecommunications, and industrial equipment. Their nonlinear voltage-current characteristics make them highly effective in surge protection, ensuring the longevity and reliability of sensitive components. Choose the right MOV surge protector to enhance your system's durability and efficiency.