The Model 8000B is a highly versatile, accurate, self-balancing instrument that meets laboratory requirements for scaling between 10-volt references or any voltage between 1 mV to 10 volts. Automatic self-calibration ensures ratios to nine significant digits with linearity deviations of less than 0.02 ppm. The Model 8000B has a 20 channel “built-in” scanner addressed individually via the Windows operating software for performing automatic measurements. Both hardware and software standard cell protection circuits are built in. In order to address the increasing demand for automated calibration of DCV ranges of most precise Multifunction calibrators, as well as the linearity verification of the long scale DVM’s, the option of fully automated bipolar measurement has been developed. This allows user to do measurement of +/- 10V range with 8000A and extend it to +/- 1200V when the 8001B extender is used. Fully documented calibration of bipolar voltages at the output of the calibrator is traceable to laboratory’s 10V reference standard. Determining the 8000B correction factors and Standardizing the source at both polarities gives additional confidence on calibration results. The Model 8000B’s range can be extended to 1200 volts with Measurements International’s precision divider extender (Model 8001B). Latest development HW and SW features of 8000B allows fully automated bipolar measurements without manual intervention. This, in combination with model 8001B extender, brings full automation of DCV ranges calibration and linearity verification of multifunction calibrators and long scale DVM’s at range up to +/- 1200V. The 4220A has 20 four terminal tellurium copper binding posts and 2 outputs consisting of 8 tellurium copper binding posts. The Model 4220B has 20 four-conductor Teflon cable inputs with 2 four-conductor Teflon cable outputs. The 4220A is also available in a 30 amp model to handle currents up to 30A (model 4220A/30).