A silicon solid state microwave spectrometer is described. It is more stable and reliable than comparable tube type circuits, is relatively low in cost, and produces a compact instrument. It is Stark‐modulated and can supply a Stark voltage of 2000 V into an external load of 1000 pF. The sweep generator employed is capable of electronic sweep durations of 0.1 to 8000 sec, using either a backward wave or reflex klystron oscillator signal source. The maximum sensitivity is limited only by the sample cell and detector noise.