New linear variable differential transformer with square coils

A novel long stroke linear variable differential transformer (LVDT) which gives a linear analog position detecting signal is investigated. This simple-structure LVDT consists of a core, an exciting coil, and two detecting coils, and it gives good linearity. The relationships among the width of the excitation coil, the core length, the number of cores, and the position of the detection coils were investigated. When the linear range is 90% or less of the core stroke, the detection error is 0.45% or less