ECE 201: Lecture 30Borja Peleato1• Impedance/admittance combinations. Applications to SSS analysisImpedances and admittances• Impedances combine as resistances, admittances as conductancesCircuit Element Impedance AdmittanceMore jargon• Impedance = Resistance + j*Reactance– Z(w) = R(w) + j*X(w)• Admittance = Conductance + j*Susceptance– Y(w) = G(w) + j*B(w)3Circuit analysis in Sinusoidal Steady State4FOR EACH W:1. Convert current and voltages into phasors2. Convert R, L, C elements into impedances.3. Analyze the circuit as a resistive circuit with constant but complex currents, voltages and “resistances” (you only need Ohm’s law, KCL, and KVL)4. Once you have your answer, transfer it back to time domain5. Add TIME components for all wThevenin/Norton equivalents• Just like we did in resistive circuits, we can replace any RLC circuit by a (complex) source and a (complex) impedance.• The method is the same:– Zth=ZN: find the equivalent impedance between the desired terminals when all independent sources are deactivated (use a PHASOR test source)– Vth: find the voltage PHASOR that appears across the desired terminals when left open circuit– IN: find the current PHASOR that appears through the desired terminals when short circuited5Example 1• If Vout=-40 sin(200t), what is i2(t)?11/7/14 ECE 201I1(t) = 1.2 cos(200t)I20.4 mF33 W0.1 H+Vout
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