Position responsive transducer with a permanent flux barrier

Claim 1

IN A POSITION-RESPONSIVE TRANSDUCER COMPRISING A MAGNETIC CORE HAVING AN AIR GAP THEREIN AND HAVING A LEG AT ONE SIDE OF SAID AIR GAP THROUGH WHICH FLUX MAY FLOW IN OPPOSITE DIRECTIONS AWAY FROM THE AIR GAP, PRIMARY WINDING MEANS ON THE CORE FOR INDUCING FLUX THEREIN TO FLOW ACROSS SAID AIR GAP, SECONDARY WINDING MEANS HAVING TWO DIFFERENT PORTIONS THEREOF ON THE CORE INDUCTIVELY ASSOCIATED WITH THE OPPOSITELY DIRECTED FLUX PATHS THROUGH THE CORE AND CONNECTED TO PRODUCE AN A.C. OUTPUT SIGNAL PROPORTIONAL TO THE DIFFERENCE BETWEEN THE INDIVIDUAL VOLTAGES INDUCED ACROSS SAID DIFFERENT PORTIONS, AND A FLUX BARRIER MOVABLE ALONG SAID AIR GAP, FROM A NULL POSITION IN WHICH THE OUTPUT SIGNAL IS SUBSTANTIALLY ZERO, TO VARY THE RESPECTIVE AMOUNTS OF FLUX FLOWING IN OPPOSITE DIRECTIONS THROUGH SAID ONE LEG, THE IMPROVEMENT WHICH COMPRISES: MEANS PROVIDING A PERMANENT FLUX BARRIER ON SAID ONE LEG AT THE NULL POSITION OF THE MOVABLE FLUX BARRIER.