Choosing transformer ratio-arm bridges

Recently published papers on transformer ratio-arm bridges have given a false impression of their operating principles. The allocation of shunt and leakage inductance to each winding of a toroidal 2- or 3-winding transformer is first considered. This is then applied to the analysis of bridges for particular practical applications proposed by Lynch, Thompson, the present author and Karo. The balance conditions are compared, when experiencing shunt stray impedance, and it is shown that three of the bridges each have their most suitable applications. This does not seem likely for the last type.