An ordinary isolated transformer isolates one circuit from another. Such a transformer is adequate for use with low gain circuits or insensitive instruments. However, if the transformers must work into a high gain load or sensitive instrumentation, noise potentials between the primary circuit and ground must be prevented from affecting the secondary circuits due to capacitive and resistive coupling between the transformers windings. Our isolation transformer employs a unique shielding technique that reduces inters winding capacitance to a large extent and increases the DC isolation.