When a TGE mov varistor for counter nominal discharge current can not meet the requirements, it should be used in parallel with multiple varistors. Sometimes in order to reduce the limit voltage, even if the nominal discharge current to meet the requirements adopted
A plurality of mov metal oxide varistor in parallel. Pay particular attention to that when the TGE metal oxide varistor theory in parallel, must be consistent with carefully selected parameters (for example: ΔU1mA≤3V, Δα≤3) paired to
To ensure uniform distribution of current
mov
2015年8月30日星期日
2015年8月28日星期五
The nominal discharge current calculation:
TGE mov varistor nominal discharge current should be greater than required to withstand inrush current or potential annual maximum surge current. The nominal discharge current should be fixed TGE MOV surge life count curve
More than 10 times the value of impact is calculated about 30% maximum impact through traffic (ie 0.3 IP) around
More than 10 times the value of impact is calculated about 30% maximum impact through traffic (ie 0.3 IP) around
2015年8月26日星期三
Varistor resistive material is a semiconductor
TGE metal oxide varistor symbol resistive material is a semiconductor, so it is a variety of semiconductor resistor. "Zinc oxide" Now a lot of use of (ZnO) varistor, it has two main material
Price element (Zn) and hexavalent elemental oxygen (O) of the composition. So from the point of view of materials, the zinc oxide metal oxide varistor basics is a "Ⅱ-Ⅵ family-oxide semiconductor."
Varistor protection, the vast majority of applications, it can repeatedly effect, but sometimes also to make it into the current fuse as a "one-off" protection device. For example, and then
On some of the short-circuit current transformer load contacts varistors. The most important feature of the TGE varistor metal oxide is added on top of it when voltage drops below its threshold "UN" when the current flowing through it is extremely small, phase
When in a shut valve, when the voltage exceeds the UN, the surge current flowing through it, is equivalent to the valve open. Using this feature, you can suppress the circuit often appear abnormal over-voltage protection
Protect circuitry from overvoltage damage.
Price element (Zn) and hexavalent elemental oxygen (O) of the composition. So from the point of view of materials, the zinc oxide metal oxide varistor basics is a "Ⅱ-Ⅵ family-oxide semiconductor."
Varistor protection, the vast majority of applications, it can repeatedly effect, but sometimes also to make it into the current fuse as a "one-off" protection device. For example, and then
On some of the short-circuit current transformer load contacts varistors. The most important feature of the TGE varistor metal oxide is added on top of it when voltage drops below its threshold "UN" when the current flowing through it is extremely small, phase
When in a shut valve, when the voltage exceeds the UN, the surge current flowing through it, is equivalent to the valve open. Using this feature, you can suppress the circuit often appear abnormal over-voltage protection
Protect circuitry from overvoltage damage.
2015年8月24日星期一
Expressions varistors deteriorate
TGE metal oxide varistor identification is a zinc oxide as the main body, add a polycrystalline semiconductor ceramic element more metal oxides, classic electronic ceramics made. Because of its unique grain boundary junction
Structure, at a certain electric field, the grain boundary by a heat conductive conduction electron-emitting instantly converted to electron tunneling conduction, as the voltage increases abruptly decreases its resistance value, having excellent non-linear volt Ante
Sex. So, when there is over-voltage, grain boundaries electron tunneling suppression overvoltage peak growth, absorbing part of the over-voltage energy, and thus play a protective role on the line or equipment.
However, regardless of varistors used in power lines or electrical lines, if the various types of overvoltage occurs frequently, then the varistors will be frequent movement to suppress the release of over-voltage amplitude and to absorb
Surge energy, protection of electrical equipment and components, which will inevitably lead to degradation in performance varistors and even failure.
Varistor failure mode there are three kinds: (1) deterioration of the performance of the leakage current increases, the breakdown voltage decreased significantly until zero; (2) burst, surge energy if overvoltage caused by too much, more than
The chosen varistor metal oxide limit the capacity, the will of ceramic varistor overvoltage occurs when suppressing burst phenomenon; (3) the perforation, especially if the over-voltage spikes high, causing varistors
Ceramic instantaneous electrical breakdown, showing perforation.
Wherein, under the premise of making grade lightning protection, varistor failure mode most of the performance degradation and perforations (ie short circuit), so when you use varistors, must with
Series with a suitable circuit breaker or fuse, to avoid a short circuit caused the accident.
Currently, the popular over-voltage protection is to TGE metal oxide varistor sizing with current limiting, over-current and deterioration warning means organically together internationally, in addition to its over-voltage protection function, but also with
To prevent deterioration of its own, resulting in a short circuit function.
Structure, at a certain electric field, the grain boundary by a heat conductive conduction electron-emitting instantly converted to electron tunneling conduction, as the voltage increases abruptly decreases its resistance value, having excellent non-linear volt Ante
Sex. So, when there is over-voltage, grain boundaries electron tunneling suppression overvoltage peak growth, absorbing part of the over-voltage energy, and thus play a protective role on the line or equipment.
However, regardless of varistors used in power lines or electrical lines, if the various types of overvoltage occurs frequently, then the varistors will be frequent movement to suppress the release of over-voltage amplitude and to absorb
Surge energy, protection of electrical equipment and components, which will inevitably lead to degradation in performance varistors and even failure.
Varistor failure mode there are three kinds: (1) deterioration of the performance of the leakage current increases, the breakdown voltage decreased significantly until zero; (2) burst, surge energy if overvoltage caused by too much, more than
The chosen varistor metal oxide limit the capacity, the will of ceramic varistor overvoltage occurs when suppressing burst phenomenon; (3) the perforation, especially if the over-voltage spikes high, causing varistors
Ceramic instantaneous electrical breakdown, showing perforation.
Wherein, under the premise of making grade lightning protection, varistor failure mode most of the performance degradation and perforations (ie short circuit), so when you use varistors, must with
Series with a suitable circuit breaker or fuse, to avoid a short circuit caused the accident.
Currently, the popular over-voltage protection is to TGE metal oxide varistor sizing with current limiting, over-current and deterioration warning means organically together internationally, in addition to its over-voltage protection function, but also with
To prevent deterioration of its own, resulting in a short circuit function.
2015年8月22日星期六
What varistor is it?
Refers to the resistance value of the TGE metal oxide varistor symbol voltage-sensitive resistor, that is, within a certain range of the resistance value of current and voltage with the voltage change.
Varistor resistive material is a semiconductor, so it is a variety of semiconductor resistor. "Zinc oxide" Now a lot of use of (ZnO) high voltage varistor, it has two main material
Price element (Zn) and hexavalent elemental oxygen (O) of the composition. So from the point of view of materials, the zinc oxide varistor is a "Ⅱ-Ⅵ family-oxide semiconductor."
Varistors useful? "Safety valve" effect TGE varistor metal oxide circuit, its greatest feature is added on top of it when the voltage is below its threshold "UN" when the current flowing through it is extremely small, the equivalent of
A shut the valve, when the voltage exceeds UN, surge current flowing through it, is equivalent to the valve open. According to the features, it can suppress the circuit often appear abnormal over-voltage protection
Protect circuitry from overvoltage damage.
Varistor resistive material is a semiconductor, so it is a variety of semiconductor resistor. "Zinc oxide" Now a lot of use of (ZnO) high voltage varistor, it has two main material
Price element (Zn) and hexavalent elemental oxygen (O) of the composition. So from the point of view of materials, the zinc oxide varistor is a "Ⅱ-Ⅵ family-oxide semiconductor."
Varistors useful? "Safety valve" effect TGE varistor metal oxide circuit, its greatest feature is added on top of it when the voltage is below its threshold "UN" when the current flowing through it is extremely small, the equivalent of
A shut the valve, when the voltage exceeds UN, surge current flowing through it, is equivalent to the valve open. According to the features, it can suppress the circuit often appear abnormal over-voltage protection
Protect circuitry from overvoltage damage.
2015年8月20日星期四
The main parameters and damaged varistor form
ZnO varistor is a zinc oxide as the main component of the metal oxide semiconductor non-linear resistance element; resistance to voltage sensitive, when the voltage reaches a certain value, the resistance quickly turned. Since the varistor has a good non-linear characteristics, through traffic, low residual voltage levels, fast action and free wheeling characteristics. It is widely used in electronic equipment, lightning protection.
The main parameters:
1, residual voltage: the highest peak occurring in the varistor voltage high current waveform by specifying its ends.
2, flow capacity: After a predetermined time interval and applying a predetermined frequency waveform current in the varistor, the maximum current amplitude variation was still varistor reference voltage within the specified range can pass through.
3, the leakage current: the role of the reference voltage, the current flowing in the varistor.
4, rated working voltage: allow long-term continuous work across the varistor frequency RMS voltage is applied. The TGE mov metal oxide varistor transient overvoltage energy absorption after their own temperature, at this voltage normal cooling, no heat damage.
Lack of varistors: (1) a large parasitic capacitance varistor having a large parasitic capacitance, typically a few hundred to several thousand pF range. In the high-frequency signal system can cause high-frequency signal transmission distortion, causing the system to normal operation. (2) the presence of the varistor leakage current leakage current index is not only related to the normal operation of the protection of electronic systems, but also related to the varistor aging and life itself.
Varistor damage in the form of: (1) When the varistor suppression of transient over-voltage energy greater than its rated capacity, the TGE Varistor for counter will damage due to overheating, mainly for shorts, opens.
The main parameters:
1, residual voltage: the highest peak occurring in the varistor voltage high current waveform by specifying its ends.
2, flow capacity: After a predetermined time interval and applying a predetermined frequency waveform current in the varistor, the maximum current amplitude variation was still varistor reference voltage within the specified range can pass through.
3, the leakage current: the role of the reference voltage, the current flowing in the varistor.
4, rated working voltage: allow long-term continuous work across the varistor frequency RMS voltage is applied. The TGE mov metal oxide varistor transient overvoltage energy absorption after their own temperature, at this voltage normal cooling, no heat damage.
Lack of varistors: (1) a large parasitic capacitance varistor having a large parasitic capacitance, typically a few hundred to several thousand pF range. In the high-frequency signal system can cause high-frequency signal transmission distortion, causing the system to normal operation. (2) the presence of the varistor leakage current leakage current index is not only related to the normal operation of the protection of electronic systems, but also related to the varistor aging and life itself.
Varistor damage in the form of: (1) When the varistor suppression of transient over-voltage energy greater than its rated capacity, the TGE Varistor for counter will damage due to overheating, mainly for shorts, opens.
2015年8月18日星期二
How to pick a good varistor?
In practice, it should be the right choice resistor. This article describes the common resistor fixed resistors, fuse resistors, thermistors, Metal oxide varistors, varistor, humidity resistance and other selection methods. ʱ??
Varistor selection
Varistors are mainly used in a variety of electronic products, over-voltage protection circuit, it has a variety of models and specifications. The main parameters of the selected varistor (including nominal voltage, maximum continuous operating voltage, maximum limit voltage, current capacity, etc.) must comply with the requirements of the application, in particular, the nominal voltage must be accurate. The nominal voltage is too high, would not achieve the over-voltage TGE metal oxide varistor basics protection, nominal voltage is too low, the varistor easily malfunction or breakdown.
Varistor selection
Varistors are mainly used in a variety of electronic products, over-voltage protection circuit, it has a variety of models and specifications. The main parameters of the selected varistor (including nominal voltage, maximum continuous operating voltage, maximum limit voltage, current capacity, etc.) must comply with the requirements of the application, in particular, the nominal voltage must be accurate. The nominal voltage is too high, would not achieve the over-voltage TGE metal oxide varistor basics protection, nominal voltage is too low, the varistor easily malfunction or breakdown.
How to judge the quality of varistor?
Varistor it with the voltage applied on top of it increasing, its resistance value can be changed from MΩ (megohms) level to mΩ (milliohms) level. When low voltage TGE metal oxide varistor application works in leakage current region, showing great resistance, leakage current is very small; when the voltage rises into the non-linear zone, when the current is within a large range, voltage changes little , showed good pressure limiting characteristic; voltage rises again, the varistor into the saturated zone, showing a small linear resistance, due to the current large, over time it will make varistor overheating or even burst.
Set the multimeter measurement 10k file, table pen connected to both ends of the resistor, the varistor should exhibit marked resistance multimeter, if you exceed this value is large, then the TGE metal oxide varistor sizing has been damaged.
Set the multimeter measurement 10k file, table pen connected to both ends of the resistor, the varistor should exhibit marked resistance multimeter, if you exceed this value is large, then the TGE metal oxide varistor sizing has been damaged.
Zinc oxide varistors application principle
Varistor is a voltage limiting protection devices. Nonlinear characteristic use varistors, when an overvoltage occurs between two poles varistor varistor voltage can be clamped to a relatively fixed voltage value, in order to achieve protection of the post-stage circuit. The main parameters of TGE Glass Coating varistors are: varistor voltage, current capacity, junction capacitance and response time.
Response time is ns grade varistor, faster than the air discharge, TVS tube slightly slower than under normal circumstances for an electronic circuit overvoltage protection to meet the requirements of its response speed. When the junction capacitance varistors are generally on the order of hundreds to thousands of pF range, in many cases should not be directly applied in the protection of high-frequency signal lines, the application of the AC circuit protection, since it greatly increases the drain junction capacitance current protection circuit is designed to take full account. Varistor flow capacity is large, but smaller than the gas discharge tube.
Varistors being protected electrical equipment or components used in parallel. When the circuit appears lightning over voltage or over-voltage transient operating Vs, TGE Metal Oxide Varistors(MOV) and the protection of equipment and components withstand Vs, due to the fast response of the varistor, it nanosecond time quickly render Nonlinear excellent electrical properties (see Figure 3 in the breakdown zone), then the voltage drop across the varistor rapidly, far less than the Vs, on such equipment and components to be protected actual withstand voltage is much lower than had voltage Vs, so that the equipment and components from over-voltage shocks.
Response time is ns grade varistor, faster than the air discharge, TVS tube slightly slower than under normal circumstances for an electronic circuit overvoltage protection to meet the requirements of its response speed. When the junction capacitance varistors are generally on the order of hundreds to thousands of pF range, in many cases should not be directly applied in the protection of high-frequency signal lines, the application of the AC circuit protection, since it greatly increases the drain junction capacitance current protection circuit is designed to take full account. Varistor flow capacity is large, but smaller than the gas discharge tube.
Varistors being protected electrical equipment or components used in parallel. When the circuit appears lightning over voltage or over-voltage transient operating Vs, TGE Metal Oxide Varistors(MOV) and the protection of equipment and components withstand Vs, due to the fast response of the varistor, it nanosecond time quickly render Nonlinear excellent electrical properties (see Figure 3 in the breakdown zone), then the voltage drop across the varistor rapidly, far less than the Vs, on such equipment and components to be protected actual withstand voltage is much lower than had voltage Vs, so that the equipment and components from over-voltage shocks.
2015年8月11日星期二
Zinc oxide varistors
"Varistor" is a non-linear voltage characteristics of the resistance of the device is mainly used in the voltage clamp circuit when subjected to excessive pressure, absorb excess current to protect sensitive devices. English name called "Voltage Dependent Resistor" abbreviated as "VDR", or called "Varistor". Varistor resistive material is a semiconductor, so it is a variety of semiconductor resistor. "Zinc oxide" Now a lot of use of (ZnO) varistor, its main material divalent element zinc (Zn) and hexavalent elemental oxygen (O) of the composition. So from the point of view of materials, the zinc oxide varistor is a "Ⅱ-Ⅵ family-oxide semiconductor." In China Taiwan, varistors called "surge absorber", sometimes also referred to as "electric shocks (surge) suppressor (absorber)."
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