811-3 The ideal transformer 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 (kxl,joL>>Eiland jOL2>>ZL 2 turns ratio 1=I1jOL-12 jaM (1)0=-I1jaM +I2(,+jOL,)(2) lIam 12M2 (2)→I Z1+/2→>(①) V1=jal+ Z+jOL§11-3 The ideal transformer 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. ( ) L L ZL k  1, jL1   Z and j 2   turns ratio N N a a N N L L = − − = = 1 2 2 2 1 2 2 1 2 ( ) ( ) 2 (1) 1 V1 I 1 jL I jM • • • = − 0 ( ) (2) 2 = − I 1 jM + I 2 ZL + jL • • (2) (1) 2 1 2 → + → = • • Z j L I j M I L   2 2 2 1 1 1 1 Z j L I M V I j L L    + = + • • •