We define the ratio of the phasor voltage to the phasor current as impedance

8-2 Superposition, source transformation and Thevenin's theorem Superposition:

《电路》（英文版）9-1 Instantaneous power

We assume=Im cos(t+a)i=Im cos(ot+B) The phase angle by which the voltage leads

Example 2: (p175-12) resistor, capacitor, and voltage source=100cos300n are all in series. If the average power dissipated by the resistor is 150W and the rms capacitor voltage is 10v, determine R and C

Frequency characteristics(Xi, xc,x,z, y, o vs o Z=R+A=R+(L+Xc)=R+ilo I

A current i at Li produces an open circuit voltage u,at L2s dyal

An ideal transformer is a useful approximation of a very tightly coupled transformer in which the coefficient of coupling is almost unity and both the primary and secondary inductive reactance are extremely large in comparison with the terminating impedance

Three-phase sources have three Q terminals called the line terminals(a, b,c). + Neutral connection--n an b+V n bn Balanced three-phase sources may

If a positive current is flowing into the(+) end of the current coil while the(+) terminal of the voltage coil is positive with respect to the unmarked end, an upscale reading is obtained