Abstract: A solid state oscillator which may be used as a microwave electronics teaching aid. The solid state oscillator is powered by a klystron power supply, and is interchangeable with a klystron. The solid state oscillator includes a circuit having inputs, through which a conventional klystron AC filament voltage is inputted. The circuit then rectifies and raises the input voltage to a higher level, and then tunes the higher level DC voltage to a resonant frequency. The raised voltage is powered by a microwave signal by means of a solid state microwave diode mounted in a wave guide.