Compensated output solid-state differential accelerometer

Abstract

Abstract A solid-state differential accelerometer employing piezotransistors for measuring acceleration or velocity of a body along a specified axis of the accelerometer. A pair of substantially identical piezotransistors are arranged back-toback along the axis through which tension and compression forces of acceleration are applied. A piezoelectrical emitter-base junction of each transistor is mechanically linked to a diaphragm portion of the transistor case that is normal to the acceleration axis. A force transferring bar links the outer surface of the transistor case diaphragm with a pliable surface of a nickel alloy protective housing of each transistor, the bar being aligned along the acceleration or force axis. The pliable housing surfaces are held together by a support ring and maintain the physical arrangement of the transistors back-to-back. A change in velocity along the force axis causes an opposing reaction by the pliable surfaces which convey changes through the force transferring bar to flex the piezotransistor diaphragms, stressing the emitter-base junction of each transistor. In related electrical circuitry, the piezotransistors have collector outputs coupled to noninverting and inverting terminals of a differential amplifier. The emitters are coupled through a common current source which allows constant conduction through the piezotransistors. Acceleration forces coupled to the transistors produces a change in output voltage proportional to the specific force input over the linear range of operation. The predominant error-producing quadratic term and the bias component of the signal are canceled and the linear output is doubled without additional amplification.

Inventors

• 👤 Little J Little
• 👤 Joe S Hunter

Bibliographic Details