Calibrating device of leakage current tester

Abstract

A calibrating device of a leakage current tester is designed to solve the following technical problems: the calibrating process is complex, wiring is complicated, the precision is hard to guarantee, the measuring range is narrow, etc. The calibrating device mainly comprises a body, an operation panel and an integrated circuit, wherein a range-changing unit of the integrated circuit adopts the reference sampling integrated mode, utilizes adjustable resistance to comprehensively cover the range from 10mu A to 400mA to realize the work mode of constant voltage and adjustable resistance and the work mode of constant resistance and adjustable voltage; the voltage drop of the leakage current in a sampling resistor is taken; and a normal / holding unit latches the maximum instantaneous leakage current the moment the tested leakage current tester gives out alarm signal, and simultaneously disconnects input of the leakage current from the range-changing unit. The calibrating device has the following benefits: the changing speed and the accuracy are substantially improved; and the calibrating device ensures the accuracy and the linearity of the alternating signal, has the advantages of high testing accuracy, wide measuring range, complete functions, perfect protection function, convenient operation and the like, and solves the technical problem of production line detection of online detection and computer control in cooperation with the unique data protection function.

Description

technical field [0001] The invention relates to a verification device, in particular to a verification device for a leakage current tester. It is suitable for the verification of leakage current testers by metrology and testing institutions at all levels, and it is also suitable for on-line testing and computer-controlled production line testing of manufacturing enterprises. The invention belongs to the field of manufacture and application of a measuring standard apparatus verification device. Background technique [0002] High-quality electrical products need to be tested for safety specifications of many items, including withstand voltage test, insulation resistance test, grounding impedance test, leakage current test, etc. The most important item in these electrical safety tests is the measurement of leakage current. Leakage current refers to the current formed by the surrounding medium or insulating surface between insulated metal parts in electrical appliances, or betw...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the technical problems existing in the verification and calibration device of the current leakage current tester, since the verification and calibration adopt a separate structure, the verification process is complicated and the accuracy is difficult to guarantee, and the narrow measurement range cannot meet the requirements of the leakage current measurement range of the medical tester, etc., provides A verification device for a leakage current tester is proposed. The device is mainly composed of three parts: the main body of the verification device, an operation panel and an integrated circuit. The integrated circuit part is mainly composed of a range conversion unit A 1 , AC / DC unit A 2 , A / D unit A 3 , display unit A 4 , normal / hold unit A 5 , polarity judgment unit A 6 and power supply unit A 7 Composition; the output end of the instrument under test is connected to the input end of the device; the range conversion unit A 1 The rational collocation of high-power resistors and different standard resistors is used to realize the integrated structure design mode, and the use of adjustable resistors enables full coverage of eleven ranges from 10μA to 400mA, and realizes the working mode of constant voltage and adjustable resistance. The output voltage adjustment of the tested instrument, combined with this verification device, can realize the working mode of constant resistance and voltage adjustment; the AC / DC unit A 2 It is a true value-effective value conversion circuit, which uses an AC-DC conversion chip for rectification and filtering; the normal / holding unit latches the maximum value of the instantaneous leakage current at the moment when the leakage current tester under test sends an alarm signal, and stores the maximum value Send A / D unit A 3 , while connecting its input with the range conversion unit A 1 disconnect;

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