Abstract: A voltage regulator is provided for producing a predetermined output voltage level. The voltage regulator has a voltage source for providing a plurality of successively increasing voltage levels at a corresponding plurality of output terminals, or taps. A controller is provided for automatically selecting, in response to an electrical control signal, the one of the taps providing a voltage level above the predetermined output voltage level. In a preferred embodiment of the invention, the selected tap is the one of the plurality of taps producing a voltage level closest to, and greater than, the predetermined output voltage level. With such an arrangement, the electronic control signal allows a convenient way to select an output voltage level closest to, and greater in magnitude than, the predetermined voltage level, thereby improving the efficiency of the regulator.

Abstract: A method of testing the impedance of an IMPATT diode operating as a pulsed oscillator at a predetermined pulse repetition frequency is shown to comprise the steps of alternately applying through different, but known, paths, a test signal to the bias line to such diode and observing the change in the test signal as reflected from the IMPATT diode.