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Selecting Evox Rifa Capacitors for Pulse Applications Begin with the peak DC application voltage Pulse applications For pulses with fast edges use this selector chart as a guideline for capacitor selection. The dV/dt figure at left is 1000 V/uS. Capacitor dV/dt specifications are for pulses equal to the capacitor rated voltage. If the peak pulse voltage is less than 0.2 uS the capacitor rated voltage, multiply the application dV/dt by the ratio of Vpeak / Vrated. In this example using a 400VDC capacitor the required dV/dt rating is 1000 V/uS x (200 Vpeak / 400 Vrated) = 500 V/uS. ≤ 1000 V 200 V dV/dt ≤ 600 V/µS ≤ 2500 V/µS DC voltage req’d dV/dt figures are approximate and depend on the capacitance and the amplitude of the pulse compared to the capacitor rated voltage. See notes at left. ≤ 1000 V/µS > 1000 V dV/dt ≤ 25,000 V/µS ≤ 2500 V/µS High frequency Sinewave current For continuous sinewave applications it is only necessary to check the ACRMS current at the operating frequency, not the dV/dt. ©2008 KEMET Less AC current AC current capability If the pulses are repetitive on high frequency basis the ACRMS current capability of the capacitor must also be checked at the operating frequency. Go to www.evoxrifa.com/n_america and download the free PCCad software. PHE426 Single metallized PP PFR Film/foil PP SMD SMD GPC Double metallized PEN SPC Double metallized PPS PHE450 Double metallized PP PHE450 Double metallized PP (up to 630 VDC) (1 and 2 section depending on voltage) (2 and 3 section depending on voltage) More AC current Datasheets are available at www.evoxrifa.com/n_america PHE448 Film/Foil 2 section PP