A direct current and even harmonic test circuit

Abstract

The application discloses a direct current and even harmonic test circuit, wherein a test meter and a resistor are connected in series to form a branch; a balance impedance and another resistor are connected in series to form another branch; the two branches are connected in parallel and then connected in series with a standard meter to form a series circuit; a voltage source is used to apply voltage to the test meter and the standard meter respectively; a current source is used to supply power to the series circuit; a diode replacement circuit is connected in series in the two branches, the diode replacement circuit comprises a power supply circuit, a field effect transistor, a current direction detection circuit and a field effect transistor driving circuit, the field effect transistor is connected to the branch and connected to the power supply circuit through the field effect transistor driving circuit, the current direction detection circuit is connected in parallel with the branch and connected to the power supply circuit, and the grounding end of the power supply circuit is connected to the branch. The application has the beneficial effect of avoiding the distortion of the power amplifier output of the current source near the zero point and improving the measurement accuracy.

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