薄膜电容器的选用取决于施加的最高电压，并受施加的电压波形、电流波形、频率、环境温度（电容器表面温度）、电容量等因素的影响。使用前请先检查电容器两端的电压波形、电流波形和频率（在高频场合，允许电压随着电容器类型的不同而改变，详细资料请参阅说明书）是否在额定值内。
The plastic film capacitor varies in the maximum applicable voltage depending on the applied voltage waveform,current waveform,frequency,ambient temperature(capacitor surface temperature),capacitance value,etc..Be sure to use capacitors within the specified values by checking the voltage waveform,current waveform,and frequency applied to them (In the application of high frequency ,the permissible voltage varies with the type of the capacitor.For detail,see the specification).
通过电容器的脉冲(或交流）电流等于电容量C与电压上升速率的乘积，即I=C x dv/dt。
由于电容器存在损耗，在高频或高脉冲条件下使用时，通过电容器的脉冲（或交流）电流会使电容器自身发热而有温升，将会有热击穿（冒烟、起火）的危险。因此，电容器安全使用条件不仅受额定电压（或类别电压）的限制，而且受额定电流的限制。
额定电流被认为是由击穿模式决定的脉冲电流（峰值电流，即由dv/dt指标所限制的）和连续电流（以峰峰值或有效值表示）组成，当使用时，必须确信这两个电流都在允许范围之内。
在高频或高脉冲条件下使用的电容器，我们推荐聚丙烯膜电容器或MPES叠片式电容器。
PPS、MPPS、MPSA系列高压聚丙烯膜电容器给出了占空比（DUTY）为15%时的额定峰峰值电流。MPP、MPH、MPA系列S校正电容器给出了额定峰峰值电流。在任何情况下都不允许超过额定峰峰值电流使用。
当实际工作电流波形与给出的波形不同时，聚酯膜电容器在自身温升为10℃或更小的情况下使用，聚丙烯膜电容器在自身温升为5℃或更小的情况下使用，电容器表面温度不许超过额定上限温度。
The pulse (or AC)current flowing through the capacitor is expressed as:l=Cxdv/dt.
Due to the fact that dissipation factor of the capacitor will generate the internal heat under the application of high frequency or high pulse current,temperature rise in it will occur and may cause deterioration of withstanding voltage.even lead to breakdown(smoking or firing).Therefore,the safety use of capacitor must be within the rated voltage(or category voltage)and the permissible current.
The rated current must be considered by dividing into pulse current(peak current)and continuous current(rms current)depending on the breakdown mode,and when using,make sure the both currents are within the permissible values.
Under the application of high frequency or high pulse,we recommend to use the polyprogylene film capacitor or CL23B stacked capacitor.
For PPS,MPPS,MPSA series high voltage polypropylene film capacitor,the catalogue gives the pemissible lp-p value with duty load 15%.For MPP,MPH,MPA series S-correction capacitor,the permissible lp-p value is also listed.In any application,operating current will not be allowed to over the permissible lp-p current value.
When the actual operating current waveform differs from the given waveform in the catalogue,the polyester film capacitor will be used within inherent temperature rise of 10℃ or less,the polypropylene film capacitor will be used within inherent temperature rise of 5℃or less ,and the capacitor surface temperature will not exceed the upper rated temperature.
不同的波形有效值按下面的公式计算
In each waveform,calculate the rms value in the following formula.
| 种类(type) | 1 | 2 | 3 | 4 |
| 波形(waveform) |  |
 |
 |
 |
| 有效值(rms) | E/√2 | E/√2 | E√t/(2T) | E/√3 |
| 种类（type) | 5 | 6 | 7 | 8 |
| 波形(waveform) |  |
 |
 |
 |
| 有效值（rms) | E√t/(3T) | E | E√t/T |  |
尽管在薄膜电容器外封装中使用了耐火性阻燃材料--阻燃环氧树脂或塑壳（UL94/V-0级），但外部的持续高温或火焰仍可使电容器芯子变形而产生外封装破裂，导致电容器芯子熔化或燃烧。
Although flame retardation epoxy resin or plastic case(UL94/V-0) is used in the coating or encapsulating of plastic film capacitor, continuous outernal high temperature or flame will break the coating layer or plastic case of the capacitor ,and may lead to melting or firing of the capacitor element.
当在电源跨线路中使用电容器来消除噪音时，不仅仅只有正常电压，还会有异常脉冲电压（如闪电）发生，这可能会导致电容器冒烟或者起火。所以，跨线电容器其安全标准在不同国家有严格规定。请使用经过安全认证的MKT61、MKP61型电容器。不推荐将直流电容器用作跨线电容器.
When using a capacitor across-the-line as means for prevention of noise ,not only the supply voltage is always applied ,but also abnormal surge such as lighting is applied ,which may lead to smoking or firing.Therefore ,the across-the-line capacitor is strictly regulated in safety standard in each country.Please use those approved products MKT61，MKP61 which conform to corresponding safety standards of different countries.
The DC capacitor will not be used in across-the-line circuit.
由于电容器充放电电流取决于电容量和电压上升速率的乘积，即使是低电压充放电，也可能产生大的瞬间充放电电流，这可能会导致电容器性能的损害，比如说短路或开路。当进行充放电时，请串联一个20～1000Ω/V或更高的限流电阻，将充放电电流限制在规定的范围内。
当多个薄膜电容器并联进行耐电压测试或寿命测试时，请为每个电容器串联一个20～1000Ω/V或更高的限流电阻。详见电容器标准。
Because the charging and dischargin current of capacitor is obtained by the product of voltabe rise rate(dv/dt)and capacitance,low voltage charging or discharging may also cause deterioration of capacitor such as shorting and open due to sudden charging and discharging current.When charging or discharging,pass though a resistance of 20 to 1000Ω/v or more to limit current.
When connecting multiple film capacitors in parallel in withstand voltage test or life test,connect a resistance of 20 to 1000Ω/v or more in series to each capacitor.(For detail,see the specification)