A.1s B.3s C.15s D.10s
A.6 B.3 C.2 D.4
A.削弱他勵(lì)磁場(chǎng) B.削弱串勵(lì)磁場(chǎng) C.削弱他勵(lì)和串勵(lì)磁場(chǎng) D.提高電壓