Mitchell, Daniel M. creator text S.l.] Mcgraw-Hill (Tx) 1988 monographic 163 p. ; Electronic apparatus and appliances Power supply Direct current 0070425973 (hardcover) 9780070425972 (hardcover) http://www.amazon.com/exec/obidos/ASIN/0070425973/chopaconline-20 http://www.amazon.com/exec/obidos/ASIN/0070425973/chopaconline-20