High voltage ceramic capacitors, also known as high-voltage ceramic capacitors used in power systems, are commonly used in products such as metering, energy storage, and voltage sharing in power systems. High voltage ceramic capacitors are made by squeezing high dielectric constant capacitor ceramics (barium titanate titanium oxide) into circular tubes, discs, or discs as the medium, and using sintering infiltration method to deposit silver on the ceramics as electrodes.
High voltage ceramic capacitors have the characteristics of wear-resistant DC high voltage and are suitable for high voltage bypass and coupling circuits. The low loss high-voltage discs have lower dielectric losses, making them particularly suitable for use in circuits such as television receivers and scanning.
As long as the high-voltage ceramic capacitor is targeted at high frequencies, the high-voltage ceramic capacitor depends on the occasion used, and its typical function can eliminate high-frequency interference.
High voltage ceramic capacitors used in high-power and high-voltage fields are required to have characteristics such as small size, high voltage resistance, and good frequency characteristics. In recent years, with the progress of materials, electrodes, and manufacturing technology, there has been significant progress in the development of high-voltage ceramic capacitors and they have been widely used. High voltage ceramic capacitors have become one of the indispensable components in high-power and high-voltage electronic products.
The use of high-voltage ceramic capacitors is mainly divided into power equipment for power transmission and distribution systems, and equipment for processing pulse energy.
Due to the unique characteristics of the power system, such as high AC voltage, high frequency, exposure to outdoor environments (-40 ° C to+60 ° C), high lightning voltage/current, and various other factors, high-voltage ceramic capacitors have always been in a difficult position in research and production. The harsh environment requires capacitors to have strong stability, that is, a small rate of change; At the same time, products such as metering, energy storage, and voltage divider require high precision, which has extremely strict requirements for partial discharge, i.e. local discharge capacity, of high-voltage ceramic capacitors in this environment: partial discharge is zero.
1 、Capacity loss has high stability with temperature and frequency
2 、Special series structure suitable for high voltage and long-term operation reliability
3 、High current climb rate and suitable for high current loop non-inductive structure
Comparison of characteristics between high-voltage ceramic capacitors and high-voltage ceramic chip capacitors:
Characteristics of high voltage ceramic capacitors
1、No authentication required
2、It is rare for ultra-high voltage to reach 7KV
3、Compared to Y capacitors, there is no need to label national certifications on the surface of the product,
4、the minimum voltage can be 16V
5、The maximum withstand voltage is 2.5 times, which is usually 1.5 times the standard test for production
Characteristics of high-voltage ceramic capacitors: commonly used in high-voltage situations.
Ceramics can be divided into Class I porcelain, Class II porcelain, and Class III porcelain,
Class I NP0, with excellent temperature, frequency, and voltage characteristics. Due to the low dielectric constant, the capacity is not large;
Class II porcelain, followed by X7R, has better temperature and voltage characteristics;
Class III ceramics have a high dielectric constant, so they can have a large capacity, but their temperature and voltage characteristics are not very good.
Ceramic capacitors are generally not large in size.
In addition, another important feature to emphasize is that ceramic capacitors often exhibit a short circuit state after breakdown (this is its weakness)
The functions of high-voltage ceramic capacitors and high-voltage ceramic capacitors are basically the same, but some details may be slightly different. So when using it, it is also important to pay attention to performance.
1 、Direct insertion high-voltage ceramic capacitors, commonly known as DIP type, are produced from 16VDC to 100KV, but mainly refer to DC and are lead type.
2 、There is an alternative type of direct insertion ceramic capacitor, which is AC ceramic capacitor, generally referring to 250VAC Y2 safety gauge capacitor and 400VAC Y1 AC safety gauge capacitor. From the name, it is obvious that the voltage of this type of capacitor refers to AC voltage, and it has safety certification from about ten countries.
3 、Chip ceramic capacitors, commonly known as SMD type capacitors, are generally represented by specifications such as 0201,0402, 0603, 0805, 1206,1210.. Chip capacitors, abbreviated as MLCC in English, have voltages ranging from 6.3VDC to 2KV or above. Of course, the higher the voltage, the more expensive it is.
4、Bolt type high-voltage ceramic capacitor. This type of capacitor is generally resistant to ultra-high voltage, and in power systems, it often refers to AC voltage. There are many models such as 40KV102K, 40KV103K, 40KV153K, etc., but the voltage inside is not DC. Because the electricity used in our homes, factories, and businesses is all AC! The technical content of this type of capacitor is quite high, and often many companies can make this shape, but they are always unable to meet the quality requirements of customers. The reason is: firstly, this type of product requires a high AC voltage, while most factories mark DC voltage, so it is eliminated during the sample delivery stage; Secondly, this type of high-voltage ceramic capacitor requires ultra-low partial discharge. The larger the partial discharge, the lower the actual withstand voltage of the capacitor. Therefore, partial discharge is the best standard for measuring the quality of a capacitor; Once again, with ultra-high power frequency, the general lead type capacitor also needs to achieve high power frequency, and this type of bolt type has higher requirements. Finally, this type of capacitor has strict material requirements because the loss, temperature coefficient, and dielectric coefficient of different materials are different
The high-voltage generator requires many high-voltage ceramic capacitors and high-capacity high-voltage capacitors. Traditionally, customers generally use high-voltage thin film capacitors, but with the continuous embodiment of the advantages of ceramic capacitors, thin film capacitors will be less and less used in high-voltage generators in the future.
The advantages and disadvantages of high-voltage thin film capacitors and high-voltage ceramic capacitors are mainly as follows:
1 、The service life of high-voltage ceramic capacitors is longer. The lifespan of thin film capacitors is three to two years, and even products with good electricity will not exceed five years. On the other hand, high-voltage ceramic capacitors are different. For example, Dike Capacitor publicly promises to design for 20 years and ensure at least 10 years of use.
2 、The internal resistance of high-voltage ceramic capacitors is smaller. This is determined by their respective structural characteristics. The internal resistance of high-voltage ceramic capacitors is very small, while thin film capacitors adopt a winding method, which leads to a larger internal resistance. Another negative impact brought about by this large internal resistance is that during the repeated charging and discharging process of the capacitor, the internal resistance will continue to increase, and it will cause the capacitor to fail in the circuit at a certain time.
3 、Relatively speaking, the voltage of high-voltage ceramic capacitors is higher. Relatively speaking, the working voltage of thin film capacitors is not as high as that of ceramic capacitors, which is a consensus;
4 、There are both advantages and disadvantages, as ceramic capacitors have a smaller capacity.
The reliability testing of high-voltage ceramic capacitors, also known as aging testing and life testing, includes many aspects of testing content:
1 、Series resistance test, insulation resistance test;
2 、Tensile testing, that is, the firmness of the lead wire and chip welding;
3 、Positive and negative temperature change rate test, that is, the change rate of capacitance under the condition of -40 ° C to+60 ° C;
4 、Aging test, high-voltage ceramic capacitors are operated in a simulated working environment for 30-60 days to test their attenuation and changes in various parameters;
5 、Voltage withstand test, including 24-hour operation test at rated working voltage; It also includes breakdown voltage, which is destructive testing. The critical voltage before the capacitor is broken down is the breakdown voltage.
6 、Partial discharge testing
7 、Lifetime testing refers to the rapid charging and discharging test of capacitors under high-frequency impulse current on the basis of aging testing. The number of charging and discharging times obtained is the charging and discharging lifespan. Note that this lifespan is obtained after long-term aging
1 、working voltage
When using DC rated voltage capacitors in AC circuits or ripple current circuits, be sure to maintain the Vp-p value of the applied voltage or the Vo-p value containing the DC bias voltage within the rated voltage range.
If voltage is applied to the circuit, temporary abnormal voltage may be generated due to resonance or switching when starting or stopping. Please be sure to use capacitors within the rated voltage range that include these abnormal voltages.
2 、Working temperature and self generated heat
(for B/E/F characteristics)
The surface temperature of capacitors should be maintained below the upper limit of their rated operating temperature range. It is necessary to consider the self heating of capacitors. Capacitors may emit self heating due to dielectric loss when used in high-frequency currents, impulse currents, etc. The applied voltage should ensure that the self generated heat and other loads do not exceed the range of 20 ℃ under ambient temperature conditions of 25 ℃. When measuring, a thermocouple with a small heat capacity of 0.1mm (K) should be used, and the capacitor should not be affected by heat dissipation from other components or fluctuations in ambient temperature.
Overheating may lead to a decrease in the characteristics and reliability of capacitors (Do not measure while the cooling fan is running. Otherwise, the accuracy of the measurement data cannot be guaranteed.)
3 、Test conditions for voltage resistance
(1) test equipment
The testing equipment for AC withstand voltage should have performance similar to 50/60Hz sine waves.
If a distorted sine wave or an overload voltage exceeding the specified voltage value is applied, it may cause a malfunction.
(2) Voltage applied method
When applying withstand voltage, the lead or terminal of the capacitor should be firmly connected to the output terminal of the withstand voltage testing equipment; Then increase the voltage from near zero to the test voltage.
If the test voltage does not gradually increase from near zero but is directly applied to the capacitor, the application should include zero crossing *. At the end of the test, the test voltage should drop to near zero; Then remove the capacitor lead or terminal from the output terminal of the withstand voltage testing equipment.
If the test voltage does not gradually increase from near zero but is directly applied to the capacitor, surge voltage may occur, leading to a fault. 0V voltage sine wave, and zero crossing refers to the position where the voltage sine passes through 0V.
4 、Failsafe
When a capacitor is damaged, failure may lead to a short circuit. To avoid dangerous situations such as electric shock, smoke, and fire caused by a short circuit, please use fuses and other components in the circuit to set up automatic fault prevention function.
If you ignore the above warnings when using this product, it may lead to short circuit in serious cases, and cause smoke or local dispersion
High voltage disc ceramic capacitors of UF Capacitors
Topdiode Group & UF Capacitors was established since 1995, as one of the professional China capacitors manufacturer and China capacitors factory, we are strong in complete management, strict quality control system, and excellent sales service.
For CT81 high votaltage disc cermaric capacitors, our normal lead time is 4 weeks. With fast delivery time, competitive prices, high quality commitment, customers can use our capacitors to replace Murata Capacitors, TDK Capacitors, Vishay Capacitors, Kemet Capacitors, AVX capacitors......
Here are some cross reference from UF Capacitors:
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UF Capacitors high voltage ceramic capacitors P/N |
UF Capacitors high voltage disc ceramic capacitors description |
Competitor P/N |
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CT81S470K20004050A000 |
CT81 47pF 2000V SL +/-10% P: 5mm Ammo RoHS Inkined type |
ECO3D470K06FK5 |
|
CT81U103M20008075B000 |
CT81 0.01uF 2000V +/-20% Y5U P: 7.5mm Bulk RoHS Y kinked |
DEBE33D103ZA3B |
|
CT81P102K30000075A000H |
CT81 1000pF 3000V Y5P +/-10% P: 7.5mm Ammo RoHS Straight lead Halogen-free |
CK45-B3FD102KYVNA |
|
CT81P222K20002075B000H |
CT81 2200pF 2000V Y5P +/-10% Bulk RoHS outside lead; P: 7.5mm halogen free |
YP202222K090B20C7H |
|
CT81P222K20000075B000 |
CT81 2200pF 2000V Y5P +/-10% Bulk RoHS Y kinked P: 7.5mm |
DEBB33D222KA2B |
|
CT81P101K20008050A000 |
CT81 22pF 3150V SL +/-10% P: 7:5mm straight lead Bulk RoHS |
DEA1X3F220JCDB |
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