00253nam a2200109Ia 4500008004100000041000800041082002400049100001500073245003800088260000900126300000800135211209s1978    xx            000 0 und d  aeng  a621.381 528 N75 SHE  aSHEPHERD W  aTHYRISTOR CONTROL OF AC CIRCUITS   c1978  a340