Standard terminology, a thin film capacitor
1 upper category temperature
Continuous work of the highest temperature determined by the capacitor design.
2, lower category temperature
Can work continuously lower ambient temperature determined by the capacitor design.
3 of the rated temperature
Can be rated voltage applied continuously the maximum ambient temperature.
4 of the rated voltage (UR)
Any temperature between the lower category temperature and rated temperature, peak may be applied continuously maximum DC voltage on the capacitor or pulse voltage.
5, category voltage (UC)
The capacitor can be the highest voltage on the capacitor continuously applied in upper category temperature.
6 temperature voltage derating
Temperature derating voltage is any temperature between the rated temperature and upper category temperature, the highest voltage on the capacitor can be continuously applied to the.
7, climate type
Said the capacitor climate category with slash separated, number
(IEC 60068 - 1: 55/100/56) 55 / 100 / 56
55 represents a lower category temperature (55 ℃) 100 said upper category temperature (+100 ℃) 56 days steady state damp heat test (56 days)
8 temperature coefficient of capacitance (a)
The capacitor in the specified temperature range varies with the temperature of the rate of capacity. Usually at 20 ℃ capacitance for reference, with one in a million per degree Celsius
(10-6/ ℃) said
(10-6/ C = 1ppm/ ℃).
Ai= (CiCo) /Co (TiTo)
The Ci: capacitor at a temperature of Ti capacity
Co: the capacitor in the To (20 ± 2) ℃ capacity
9 insulation resistance (I.R.) / time constant (T)
Leakage insulation resistance of capacitor charging voltage applied after a minute and flowing through the capacitor current value, unit M. The time constant for the product of insulation resistance and capacitance. Usually expressed in seconds, the formula is as follows:
T [S] = I.R. [M] C [uF] *
In general, the insulation resistance is used to describe the insulation characteristics of small capacity capacitor, time constant is used to describe the large capacity (such as: CR>0.33 uF) insulation characteristics of capacitor.
10 the loss tangent (TG delta)
In the sine wave voltage specified frequencies, power loss divided by the capacitor capacitor wattless power.
11 self-healing (only for metallized film capacitor)
Metallic coatings on metallic film by vacuum evaporation of the metal deposit on the film thickness, only tens of nanometers, when there are weaknesses, impurity medium, local breakdown may occur, produced by the electric arc discharge in the position of the energy is enough to make the metal coating evaporation electrical breakdown point in the vicinity, the the breakdown and spaced around the plate, capacitor electrical properties can be restored to normal.
Two note, the use of film capacitor:
1, the working voltage
The plastic film capacitor depends on the highest voltage applied, the applied voltage waveform, current waveform, frequency, ambient temperature (capacitor surface temperature), capacitance effect etc.. Please check the capacitor before using the voltage waveform, current waveform and frequency in the rated value.
2, the working current
By means of pulse capacitor (or AC) current is equal to the product of capacitance and voltage rising rate of C, that is I = C * dv/dt
Because of the loss of the capacitor, the use of high frequency or high pulse conditions, by means of pulse capacitor (or AC) current will cause the capacitor of heating and temperature rise, there will be thermal breakdown (smoke, fire) risk. Therefore, safety use of capacitor must be within the rated voltage (or category voltage) restrictions, and restricted by the rated current.
The rated current is determined by the pulse current voltage (peak current, namely dv/dt index limit) and continuous current (expressed as peak or RMS), when using, must be sure that the two current within the allowable range.
Capacitor used in high frequency or high pulse conditions, we recommend polypropylene film capacitor.
In any case are not allowed to exceed the rated peak current.
When the waveform and given the actual current waveforms are not at the same time, the capacitor surface temperature will not exceed the rated maximum temperature.
3 power supply for electromagnetic interference suppression capacitor
3.1 when to eliminate noise using a capacitor across the line in the power circuit, not only the normal voltage, but also abnormal pulse voltage (such as lightning), which may cause the capacitor smoke or fire. So, the across-the-line capacitor is strictly regulated in safety standard in different countries. Please use MKP, CL62, CBB62 capacitor through the security certification.
3.2 X2 capacitors for electromagnetic interference suppression
Applicable to not in capacitor failure cause electric shock dangerous situations, such as power across the line connection, pulse can bear 2.5KV.
The 4 capacitor charging and discharging
Because the product of capacitor charging and discharging current depends on the capacitance and voltage rising rate,
The voltage reducing rate of three.
Different varieties (material) voltage products used in the rated temperature and limit temperature, maximum temperature on reduction rate.
Polyester film capacitors used in high frequency conditions, due to the capacitor itself, the heat will make the capacitor temperature increases, the loss angle value will be bigger.
The capacitor used in self heating temperature in electronic circuit the following 10 or 10, and not more than its rated maximum temperature.
Dielectric varieties upper rated temperature using upper temperature limit voltage
Polyester MPE 85 ℃ of 105 ℃ rated voltage x 1.75
Polypropylene MPP, NPP
Please call our direct line to consult with us：
