Magnetic Fields of Twisted-Wire Pairs

On the basis of an expression given by Buchholz for the magnetic-vector potential for an infinitely long twisted-wire pair, the expressions for the external component-flux densities in cylindrical coordinates have been developed. These expressions checked very well with data obtained in the proximity of precisionwound twisted-wire pairs. A generalized graph for various radii and pitch lengths has been developed to enable the design engineer to quickly predict the strength of the magnetic field for all three spacial components at distances in the proximity of a twisted-wire pair.