KVD-700 Precision Kelvin-Varley Voltage Divider

• Primary Calibration grade 100 kΩ Kelivin-Varley Voltage Divider
• Used by National Measurement Institutes around the world
• Built in Wheatstone Bridge allows for a self calibrating circuit
• Employees "Zero tempco foil resistors"
• Direct replacement for Fluke 720A

The KVD-700 is a primary calibration grade voltage divider employing the Kelvin-Varley circuit. It is a highly accurate, stable, and linear primary ratio standard suitable for use in many applications requiring known voltage or current ratios. In particular, the KVD-700 Kelvin-Varley Voltage Divider is especially appropriate for use in bridge circuits, providing two legs of a bridge with a very well known ratio.

The KVD-700 has a resolution of 0.1 ppm and an absolute linearity of 0.1 ppm. It has a 1.0 input and a 1.1 input to allow over-ranging. Temperature coefficient

of linearity is 0.1 ppm/ºC, and power coefficient of linearity is 0.2 ppm/W.

The KVD-700 Kelvin-Varley Voltage divider incorporates a number of advanced features making for convenience and high performance. These include: self-calibration capability; state of the art nominally "zero tempco bulk metal foil resistors"; Kel-F mounted low-emf tellurium copper binding posts; sealed internal calibration potentiometers; and a convenient operating guide attached to the unit.

The KVD-700 features a built-in Wheatstone bridge self-calibration circuit so that the unit may be calibrated with a minimum of external instruments and

without requiring another voltage divider.

The KVD-700 Kelvin-Varley Voltage divider employs precision resistors which have been aged, temperature and power cycled to maximize

long-term stability, and matched to minimize temperature and power coefficients effects. The most significant decade is sealed in an oil bath to minimize

temperature coefficient effects.

The switches used have gold plated solid silver alloy contacts for long life, minimum contact resistance, and no tarnishing. Gold also allows the use with low level signals. The switches have multiple wiper contacts to provide stable low contact resistance. The main switches are sealed.

High quality gold plated tellurium-copper binding posts serve to minimize the thermal emf effects which would artificially reflect a change in dc resistance measurements. They are mounted to the case on special Kel-F washers to insure low leakage. All other conductors within the instrument, as well as the solder employed, contain no metals or junctions that could contribute to thermal emf problems.

The front panel is clearly labeled showing step size for each decade. Maximum voltage and current limits are indicated as well. The unit may be mounted in a standard 19-inch rack.

Applications include

linearity determination

the measurement of voltage and resistance

the calibrationof other dividers, potentiometers or similar devices involving both voltage and current.