Self-balancing instrument

Claim 1

A multi-range, self-balancing apparatus, comprising a. voltage generating means comprising a slide resistor having a movable brush and for generating an output standard voltage corresponding to the position of said brush; b. phase compensating means comprising is a voltage dividing circuit, a first capacitor and a non-inverting input amplifier having a variable amplification factor, said voltage dividing circuit comprising a resistor and a first range-changing attenuator to divide the output standard voltage of said voltage generating means, said output standard voltage being applied to said input amplifier and said amplifier providing an output signal through said first capacitor to the voltage dividing point of said voltage dividing circuit thereby to provide a phase compensated output signal; c. a difference signal generator and DC-AC converter means for converting the difference between said output signal from said phase compensating means and a measuring voltage, into an AC signal; (d) output means having a second range-changing attenuator for receiving said AC signal from said difference generator and DC-AC converter means and means for interlocking said second attenuator with said first attenuator whereby the product of the multiplication of the attenuation ratio of said first attenuator and the attenuation ratio of said second attenuator is constant, said output means supplying an output signal in accordance with the attenuation ratio of the said second attenuator; e. balancing motor means having a control phase and a shaft, said shaft being connected to said brush of said slide resistor of said voltage generating means, said output signal from said output means being applied to said control phase of said motor; and f. white noise generator means comprising a Zener diode and means for connecting the output terminals of said white generator to said phase compensating means, whereby said white noise output is superposed on said phase compensated output signal from said amplifier and thereafter operated upon by said difference generator and DC-AC converter means and said output means and subsequently applied to said motor means thereby to keep the dead zone small and constant for all ranges.