Answer: B. 85. What is differential equation whose solution is vC(t)= - 20e-1000t+20 V t≥0.
85. What is differential equation whose solution is vC(t)= - 20e-1000t+20 V t≥0. A. (dvC/dt)+100vC= -10u(t) B. (dvC/dt)+1000vC= -10u(t) C. (dvC/dt)+100vC= 10u(t) D. (dvC/dt)+1000vC= 10u(t) E. (dvC/dt)+1000vC= 20000u(t)
Solution: vC(t)= - 20e-1000t+20 V RC-circuit with step-response. General equation is
with general solution of the form vC(t)=[vC(0) – vC(∞)]e-t/Tc + vC(∞) vA=vC(∞)=20V TC=RTC=1/1000; Thus we have
Answer: E.
For inductor voltage _____ current by ____ degrees. For capacitor voltage _____ current by ____ degrees. A. lags,…90,…, leads, …, 90 B. leads,…90,…, lags, …, 90 C. leads,…180,…, lags, …, 90 D. leads,…90,…, lags, …, 180 E. lags,…90,…, leads, …, 180 Solution: For inductor voltage leads current by 90 degrees. For capacitor voltage lags current by 90 degrees. Answer: B.
The real part of impedance is called ______ and imaginary part is called _____. The real part of admittance is called ______ and imaginary part is called _____. A. resistivity,…conductivity,… susceptance,… conductance B. reactance,…resistance,… susceptance,… conductance C. resistance,…reactance,… susceptance,.. conductance D. reactance,…resistance,…conductance,…susceptance E. resistance,…reactance,…conductance,…susceptance
Solution: Z = R ± jX Y = G ± jB The real part of impedance is called resistance and imaginary part is called reactance. The real part of admittance is called conductance and imaginary part is called susceptance.
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Multiplying by 1000 gives
