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

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

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

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

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

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

《电路》（英文版）9-1 Instantaneous power

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

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

sinusoidal current or voltage at a given frequency is characterized by only two parameters an amplitude and a phase angle. The complex representation of the voltage or current is also characterized by these same two parameters