| 摘要 |
1,223,810. Measuring force electrically. GENERAL ELECTRIC CO. July 29, 1969 [Aug. 9, 1968], No.38039/69. Heading G1N. [Also in Division G3] A transducer for measuring force comprises two pairs of semi-conductor strain gauges mounted so that each pair is stressed oppositely by the applied force, each pair being connected in a Wien bridge oscillator circuit so that the strain gauge resistance determines the oscillator frequencies, which are therefore varied differentially by the force whose magnitude is indicated by the frequency difference. In one embodiment, Fig. 2, for measuring acceleration, a constant stress cantilever beam 15 of n-type single crystal silicon is rigidly secured at one end to a support 16 and carries a mass 17 at the other end. Two pairs of strain gauges R5, R6 and R7, R8 formed by elongated strips of p-type silicon are formed on the opposite faces, each pair being connected in a Wien bridge oscillator circuit, Fig. 1, (not shown), initially adjusted to the same resonant frequency. When subjected to acceleration normal to the plane of beam 15, the resistances of the strain gauge pairs vary oppositely, producing a frequency difference between the oscillators which is measured at mixer 13. Another embodiment, Fig.3, for measuring weight comprises live vertical load columns 20, 21 of single crystal silicon, mounted between a horizontal base 22 and load distributor 23, the strain gauges R5-8 being formed on one column 21 in perpendicular directions so that they are stressed oppositely by an applied weight. The remaining circuitry may be formed as a monolithic integrated circuit mounted on column 22. |
