The 7481 is an 8½-digit digital multimeter with high resolution of 0.01 ppm. It is suitable for use in research and development fields or calibration organizations, and calibration of inspection systems for electronic components or semiconductors. The 7481 achieves high-resolution measurement such as 10 nV for DC voltage measurement, 100 fA for DC current measurement and 1 μΩ for resistance measurement, and also guarantees high relative accuracy 5 ppm per year for voltage measurement.
In addition, the self-calibration function allows high-accuracy measurement at any time, and external calibration can be performed with a smaller number of standards. The 7481 has not only the GPIB and the USB as interface for automatic systems but also input terminals on the rear panel for easy system configuration.
The 7481 is a high-performance digital multimeter with 8½-digit display for DC voltage or resistance measurement (119 999 999) and 7½-digit display for DC current measurement (11 999 999). As for DC voltage ratio measurement, maximum 8-digit display is possible. Consequently, this is the best used as standard and for high-accuracy measurement.
|DC voltage||Resistance||DC current||Voltage ratio|
|Maximum display||119 999 999||119 999 999||11 999 999||99 999 999|
|(Condition)||10 V range||10 kΩ range||1000 μA range||10 V range|
*Relative accuracy: ppm of reading ± ppm of range, 23°C ± 1°C, 24 hours
All you need to perform external calibration for the 7481 are two sources: a DC voltage standard (10 V) and a resistance standard (10 kΩ). By the two-source calibration and the self-calibration function, all rages of DC voltage, DC current and resistance are calibrated and internal errors due to ambient temperature change can be removed. As a result, high-accuracy measurements are guaranteed. Calibration values are stored in the internal memory together with its calibration date, and these data can be read out by the GPIB or USB.
The 7481 adopts a self-developed multi-scope integration system for A/D conversion. So, it realizes high-precision linearity and excellent stability as standard, making it possible to perform high-accuracy measurements. The following figure shows the stability at 0 V input in the 10 V range.
The 7481 offers measurement with less dispersion by its low-noise ranging amplifier. The following figure shows the integration time and effective values (rms) of display dispersion at 0 V input in the 100 mV range.
In ratio measurement, the reference DC voltage is measured by using the 4 WΩ measurement terminal in addition to normal DC voltage measurement, and its voltage ratio is gained by calculation. Using this function, it is possible to measure attenuator voltage division ratio and electric power, eliminating error factors of the external supply source in resistance measurement.
Efficient PASS/FAIL judgement is available by setting threshold values for inspection of electronic components such as resistors and semiconductors. Judgment results PASS or FAIL are displayed as measurement results on the screen, and also are output to the COMPARATAOR output terminal.
The maximum 10,000 samples can be set. Statistic operation results such as maximum value, minimum value, average, dispersion and standard deviation (σ) are displayed.
Up to 50,000 measurement data can be stored in the internal memory (RAM).
The front and rear input terminals can be controlled externally via the GPIB, USB or LAN (option). It can prevent switching errors between the front and rear input.
In 4-wire resistance measurement, contact check on the current source and voltage measurement points are performed. Measurement errors due to wrong connection or contact failure can be judged in advance.