BIFILAR AC-DC RESISTOR USING A MICROWIRE

Bifilar ac-dc resistors of 6.45 k Omega to 103.2 k Omega consisting of a microwire and a fused silica bar, with extended nominal resistance, improved stability and reduced mechanical sensitivity, have been inve stigated and fabricated. In this resistor, a fused-silica rectangular bar was inserted between the wires of the bifilar loop to support the microwires and to increase capacitance between the wires. From resista nce measurements at ac and de for several resistors, the frequency cor rection factor was evaluated to be less than 2 x 10(-8) in the frequen cy range from de to 1.6 kHz, The resistors can be used as transportabl e standards for direct comparison with the quantized Hall resistance a t both de and ac, far calibration of the ac standard resistors and the ratio of transformer bridges.