The 4279A 1MHz C-V Meter offers the optimum solution for increasing quality and throughput when measuring the capacitance vs bias voltage characteristics of semiconductors. The 4279A measures capacitance over a range of 0.00001pF to 1280.00pF with a basic accuracy of 0.1% and a 6 digit display resolution while sweeping the DC bias voltage. An internal, programmable dc bias sweep source with a 0.1% voltage accuracy throughout the +/-38V range assures very low measurement error due to low bias voltage uncertainty. It makes the 4279A ideal for the precise characterization and testing of varactor diodes, MOS diodes, etc. Measurement time can be selected from three modes of 10ms, 20ms and 30ms/meas to maximize productivity. The 4279A's very fast ranging and high speed GP-IB data transfer capabilities reduce test time. The automatic bias polarity control feature allows quick selection of the correct polarity bias voltage for the device under test. This new function eases manual testing of samples in incoming/outgoing inspection and provides a simple method of polarity control for automatic test systems.