GB1128318A - Electro-mechanical transducer - Google Patents

Abstract

1,128,318. Audio transducers. WESTINGHOUSE ELECTRIC CORP. 30 Sept., 1966 [28 Oct., 1965], No. 43809/66. Heading H4J. [Also in Division H1] Mechanical movements of a phonograph pickup or microphone diaphragm modulate the surface potential of a semi-conductor element to produce electrical signals. In one embodiment, Fig. 1, the spacing of a resilient arm 32 from the gate electrode of an MOS transistor 20 is varied by movements of stylus 38 to modulate the conductivity of the channel. The output of the transistor may be fed to an amplifier which is preferably built into the silicon wafer 22 containing the transistor. Cooling fins 18 are provided on the pick-up head. Arm 32 is shown fixed at one end 34 but may alternatively be pivoted at an intermediate point to magnify the variation in spacing between the member and the gate. In another embodiment comprising an MOS transistor with two channels extending between a central drain region 127 and two source regions 126, 128 (Fig. 3), the electrically biased arm 132 is vibrated laterally in response to motion of the stylus 137 to vary the surface potential in opposite senses in the two channels which form part of a potentiometer network. The use of tunneling devices and avalanche transistors in pick-ups is also suggested. Reference has been directed by the Comptroller to Specifications 1,036,837, 1,088,793 and 1,088,794.