Abstract: An oscillator having: (A) a transistor for producing an oscillating output signal at an output electrode of the transistor. The oscillator includes; (B) a bias circuit for producing a bias signal for the transistor, said bias circuit including an amplifier coupled to the output electrode of the transistor; and (C) a circuit coupled between an output of the amplifier and a control electrode of the transistor, for isolating the bias signal provided by the amplifier from the oscillating signal.

Abstract: An oscillator having: a transistor; a resonant circuit coupled between an output electrode of the transistor and a control electrode of the transistor; and a dc bias circuit for the transistor. The dc bias circuit comprises: a voltage producing circuit and a differential amplifier. The differential amplifier includes: a first input coupled to a fixed reference voltage; a second input coupled to the voltage producing circuit, such voltage producing circuit producing a voltage at the second input of the difference amplifier related to current passing through the output electrode of the transistor; and an output coupled to the control electrode of the transistor.

Abstract: A membrane module which includes a unitary, curved, backing support which retains all the U bends, serially connecting the membrane tubes, in a sealing relationship, and which includes an annular permeate-collector ring system at the end of each membrane tube and channels with a permeate manifold passageway, to provide efficient removal and easy cleaning of the permeate flow path.