The T-type circuit structure consists of three MOS FET relays that help reduce the leakage current to a minimal level without affecting the test equipment's inspection accuracy, allowing high-precision measurement and decreasing maintenance frequency of the test equipment. Mechanical reed relays have extremely low leakage current but require replacement on a regular basis. Such maintenance work may substantially affect the production efficiency, so adoption of solid-state relays has been long desired as its longer lifecycle. MOSFET relays have been considered unsuitable for precise electrical tests due to leakage current, and were not used in test equipment which requires high reliability. By combining multiple MOSFET relays, this unit achieves the needed low leakage current while eliminating the need for replacement of mechanical relays.