| CPC G01R 27/30 (2013.01) [G01R 35/005 (2013.01)] | 17 Claims |
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1. A double-balance electronic test apparatus for measuring inductance, capacitance, and resistance, the double-balance electronic test apparatus comprising:
a testing circuit that comprises:
a testing ac waveform generator that produces a test waveform comprising a test phase P1 and a test amplitude A1;
a testing ac waveform detector in electrical communication with the testing ac waveform generator and biased at test voltage V1 in operation; and
the testing circuit receives an impedance device under test comprising a test impedance Z1, such that the impedance device under test is in electrical communication with the testing ac waveform generator, the testing ac waveform detector, and a virtual ground, and the impedance device under test receives the test waveform from the testing ac waveform generator, wherein the testing circuit produces a test current I1 that flows through the impedance device under test in response to the test impedance Z1 of the impedance device under test subjected to the test waveform;
an auto balance circuit in electrical communication with the testing circuit and that comprises:
a current amplifier in electrical communication with the virtual ground and that produces an auto balance current I2 based on a voltage of the virtual ground and produces an auto balance waveform comprising a auto balance phase P2 and an auto balance amplitude A2;
an auto balance ac waveform detector in electrical communication with the current amplifier and biased at auto balance voltage V2 in operation; and
an auto balance reference ac resistor comprising an auto balance impedance Z2 in electrical communication with the auto balance ac waveform detector, the current amplifier, and the virtual ground, such that the auto balance reference ac resistor receives the auto balance waveform from the current amplifier, wherein the auto balance circuit produces an auto balance current I2 that flows through the auto balance reference ac resistor in response to the auto balance impedance Z2 of the auto balance reference ac resistor subjected to the auto balance waveform; and
a coarse balance circuit in electrical communication with the testing circuit, the auto balance circuit, and the virtual ground and that comprises:
a coarse balance ac waveform generator that produces a coarse balance waveform comprising a coarse balance phase P3 and a coarse balance amplitude A3;
a coarse balance ac waveform detector in electrical communication with the coarse balance ac waveform generator and biased at coarse balance voltage V3 in operation; and
a coarse balance reference ac resistor comprising a coarse balance impedance Z3 in electrical communication with the coarse balance ac waveform detector, the coarse balance ac waveform generator, and the virtual ground, such that the coarse balance reference ac resistor receives the coarse balance waveform from the coarse balance ac waveform generator, wherein the coarse balance circuit produces an coarse balance current I3 that flows through the coarse balance reference ac resistor in response to the coarse balance impedance Z3 of the coarse balance reference ac resistor subjected to the coarse balance waveform.
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