Calibrating device for AC and DC leakage current tester

Abstract

The invention discloses a calibrating device for an AC and DC leakage current tester, which comprises an input device, a display device, a main control MCU (Microprogrammed Control Unit), an ADC (Analog Digital Conversion) voltage sampling unit, an DAC (Digital Analog Conversion) voltage reference generating unit, a DDS (Direct Digital Synthesis) AC waveform generating circuit, an input selector switch, an error amplifier, a time constant table, an AC and DC automatic range voltage meter, an automatic range resistor meter, an output selector switch matrix, an output power amplifier, an AC / DC true root mean square converter, an AC and DC voltage output module, an AC and DC current output module and an AC and DC small current simulating electronic load module. The calibrating device has higher frequency accuracy and stability without being externally connected with a computer; various functions are directly switched through the input device and the display device which are controlled bythe main control MCU, and various detection parameters are set; and the AC and DC automatic range voltage meter, the automatic range resistor meter, the time constant table, the AC and DC voltage output module, the AC and DC current output module and the AC and DC small current simulating electronic load module can be corrected in a soft correction manner.

Description

Technical field [0001] The invention relates to the technical field of testing, in particular to a verification device of an AC and DC leakage current tester. Background technique [0002] Leakage current is one of the main parameters of current electrical products for product safety testing, and its importance has exceeded that of insulation resistance testing. Relevant industries stipulate that the safety voltage is 36V and the safety current is 10mA. The reasons are as follows: The degree of harm to the human body from electric shocks mainly depends on the size of the current passing through the human body and the length of the power-on time. The greater the current intensity, the greater the fatal danger; the longer the duration, the greater the probability of death. The minimum current value that can cause people to feel is called sensing current, AC is 1mA, DC is 5mA; the maximum current that a person can get rid of after an electric shock is called escape current, AC is 1...

AI Technical Summary

Problems solved by technology

[0005] 1. The degree of automation is not high. Many instruments need to use potentiometers to adjust the output, which fails to reflect the advantages of automated measurement

[0006] 2. The calibration function is only a simple stacking of instruments according to the requirements of the national verification regulations, not a set of multi-functional comprehensive instruments

[0007] 3. Insufficient functions, unable to meet all the requirements of the items in the national verification regulations, basically unable to verify the time constant

[0008] 4. Internal calibration is inconvenient, and most of them still use the backward method of potentiometer adjustment for calibration

[0009] 5. The function is backward, and the load resistance box is used to repeatedly adjust the leakage current

[0010] 6. The measurement range is narrow, the measurement range of the working frequency is small, and the practicability and applicability of the instrument are not strong

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