5 4 0 8 , ▁exhib it ▁similar ▁changes ▁in ▁j unction ▁capac it ance , ▁with ▁the ▁exception ▁that ▁the ▁B A   1 0 2 ▁poss esses ▁a ▁specified ▁set ▁of ▁characteristics ▁in ▁relation ▁to ▁j unction ▁capac it ance ▁( where as ▁the ▁ 1 N 5 4 0 8 ▁does ▁not ) ▁and ▁the ▁" Q " ▁of ▁the ▁ 1 N 5 4 0 8 ▁is ▁less . ▁ ▁Before ▁the ▁development ▁of ▁the ▁var ic ap , ▁motor ▁driven ▁variable ▁capac itors ▁or ▁s atur able - core ▁react ors ▁were ▁used ▁as ▁elect r ically ▁cont roll able ▁react ances ▁in ▁the ▁V CO s ▁and ▁filters ▁of ▁equipment ▁like ▁World ▁War   II ▁German ▁spectrum ▁analyz ers . ▁ ▁See ▁also ▁▁ ▁H eter ost ruct ure ▁bar rier ▁var act ors ▁are ▁symmetric ▁sem icon duct or ▁devices ▁with ▁variable ▁capac it ance . ▁ ▁Fer ro elect ric ▁capac itors ▁have ▁a ▁variable ▁capac it ance ▁due ▁to ▁h yst er esis ▁effects . ▁ ▁D iff usion ▁capac it ance ▁ ▁References ▁ ▁Further ▁reading ▁ ▁Mort enson , ▁Kenneth ▁E . ▁( 1 9 7 4 ). ▁Variable ▁capac it ance ▁di odes : ▁the ▁operation ▁and ▁character ization ▁of ▁var actor , ▁charge ▁storage ▁and ▁P IN ▁di odes ▁for ▁R F ▁and ▁mic row ave ▁applications . ▁D ed ham , ▁Mass .: ▁Ar tech ▁House . ▁ ▁Pen field , ▁Paul ▁and ▁Raf use , ▁Robert ▁P .