Abstract: Resistor voltage dividers are commonly used to create reference voltages, or to reduce the magnitude of a voltage so it can be measured. Many measurements in test and measurement or calibration applications regularly require accuracies within the sub-part per million (ppm) range, e.g. 0.1 ppm to 1.0 ppm. However, the continued drive for improved accuracy in calibration, standards, and measurements on circuits and components means many measurements and measurement systems are operating at 50 parts per billion (ppb) and below to approximately 10 ppb. At these levels even relatively simple passive elements such as voltage dividers cannot be used without calibration and that these calibrations may be required at frequencies substantially higher than the other elements within the test and measurement equipment. Accordingly, the inventors have established a self-contained voltage divider with internal calibration allowing the voltage divider to be calibrated for every measurement if necessary.

Abstract: A more precise and cost effective means than previously commercially available for measuring alternating currents up to 100 amperes in the frequency range from direct current to 100 kilohertz can be measured with precision approaching 0.001% employs a shield around a resistive network. The shield is electrically isolated from the resistive network, but acts as a heat sink to draw heat generated by the resistive network away, promoting fast stabilization times. The shield also provides electrical shielding from outside interference allowing the geometric arrangement of elements in the resistive network to minimize induced inductance and capacitance.