Low-noise operation of m.o.s. transistors in common-gate connection

The variations of noise factor with source resistance, for metal-oxide-semiconductor transistors (m.o.s.t.s) in the common-gate and the common-source connections, show a minimum. A theoretical explanation is derived in terms of equivalent noise generators, and compared with measurements on these devices. It is thereby shown that common-gate operation has advantages when low noise is required.