This paper provides a detailed study to design novel gallium nitride (GaN) current transducers (CT), suitable for in-situ current monitoring. The paper is result of an ITSIA project funded through the EPSRC Challenge Network. Published as a featured article in the Semiconductor Today Magazine. The designs given resulted in successful fabrication of the first ever current magnetic sensors that are now being embedded in SiC inverters through a recent IDP15 InnovateUK project. A joint EPSRC proposal, GaN SPICe, is currently being prepared on monolithic integration of normally-off GaN transistors with CT for highly efficient power electronics conversion systems.