Question

Nonideal Capacitor Impedance No electronic component is perfect. All capacitors have small imperfections called "parasitics", that deviate from an ideal capacitor's behavior. A model of a realistic capacitor for automotive switching applications is shown below. It is rated for 250 volts. REAL ESR 3m0 logs and electrolyte) ESL 9nH (leg wires) IDEAL R76 MKP H7 Leakage 500MC C1 :11.2nF C1 =11.2nF a) At rated voltage, at DC, what current does the ideal capacitor draw? What current does the real capacitor draw? b) Compare the impedance of real and ideal capacitors at a medium frequency of 10 kHz, What is the percent difference in magnitude and angle difference in degrees? c) As frequency gets very high, the ESL (equivalent series inductance) becomes don over all the other parts. How high of a frequency is needed for the ESL's reactance to be as large as the ESR (equivalent series resistance)?

Answer 1

At Yaked DC voltuge ideal acitor drawr cap Real copacitor drows I = + LCakagc EJR+ L 250 0.033 + 500x = 0.5 X10 A Reel cepacthor I= 0.5 MA Ickel copachor 2= jwe janfc Z= -jl. 40) x 4= 1.4)1x1 -90 ideal copocitor imprdonce * 50ox10 j anfc Real copacitos Ze = 0.033+ janfl + janfe .sooxl ) 0-033 + J (anx10x ZR %3D (avome)+ janxioxi2" 89.837 Real ZR percent diferena in monde c 0% O.163 Ongle difference

c) ESR= O. 033 S ESL = 21FL E SL > ES R 21FL > O.033 f > 0.033 f> 583 568,1247 fox ESL to be more thon ESR, freaueney must be more than 583. 568 KH3