720A Kelvin-Varley Divider

General specifications

Ratio range

0 to 1.0 (1.0 input tap) and 0 to 1.1 (1.1 input tap)

Resolution

0.1 ppm of input with seven decades

0.2

Absolute linearity

(At calibration temperature and without the use of a correct chart) ±1.0 ppm of input at dial

settings of 1.1 to 0.1, ±0.1 (10S)^1/3 of input at dial settings (S) of 0.1 to 0

Absolute linearity stability

(Without self-calibration) ±1.0 ppm of input/yr at dial settings of 1.1 to 0.1, ±1.0 (10S)(2/3) ppm

of input/yr at dial setting (S) of 0.1 to 0

Note: Absolute linearity is defined as the linearity between max and min output voltages. The self-calibration procedure may be used at any time to reset absolute linearity to ±0.1 ppm of input.

Temperature coefficient of linearity

±0.05 ppm of input ºC maximum at dial settings of 1.1 to 0.1

Short-term linearity stability

Under typical standards laboratory conditions (temperature maintained within ± 1 ºC) and with

an applied voltage of up to 100V, stability of linearity is ± 0.01 ppm/24 hours and ± 0.1 ppm/30 days

Power coefficient of linearity

±0.2 ppm of input/W max at dial settings of 1.1 to 0.1; ±0.2 (10S)2 ppm of input/W max at dial

settings (S) of 0.1 to 0

Maximum end errors

Zero error at output low: 0.004 ppm of input

Zero error at input low: 0.05 ppm of input

Full-scale error: 0.05 ppm of input

Maximum input voltage

1000 V on 1.0 input terminal, 1100 V on 1.1 input terminal

Thermal voltages

±0.5 μV max

Input resistance

100 kΩ ±0.005% at 1.0 input terminal at 25 °C, 110 kΩ ±0.005% at 1.1 input terminal at 25 °C

Temperature coefficient of input

resistance

±1 ppm per °C max

Size

14 cm H x 48.2 cm W x 33 cm D, rack mounted (5.5 in H x 19 in W x 13 in D)

Weight

8.15 kg (18 lb)