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

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

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

Example 1: If 0=4v2 cos\tV, Z=2/600Q2 Find p(t)and P. Solution:

《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

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