Kibble balance is an electromechanical measuring instrument that measures the weight of a test object very precisely by the electric current and voltage needed to produce a compensating force.
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13 Facts About Kibble balance
2.
Kibble balance is a more accurate version of the ampere balance, an early current measuring instrument in which the force between two current-carrying coils of wire is measured and then used to calculate the magnitude of the current.
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3.
The Kibble balance operates in the opposite sense; the current in the coils is measured using the definition of the Planck constant to "measure mass without recourse to the IPK or any physical object".
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4.
The Kibble balance determines the weight of the object; then the mass is calculated by accurately measuring the local Earth's gravity with a gravimeter.
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5.
Principle that is used in the Kibble balance was proposed by Bryan Kibble of the UK National Physical Laboratory in 1975 for measurement of the gyromagnetic ratio.
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6.
In 1978 the Mark I watt Kibble balance was built at the NPL with Ian Robinson and Ray Smith.
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7.
Main weakness of the ampere Kibble balance method is that the result depends on the accuracy with which the dimensions of the coils are measured.
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8.
The Kibble balance uses an extra calibration step to cancel the effect of the geometry of the coils, removing the main source of uncertainty.
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9.
Bryan Kibble worked with Ian Robinson and Janet Belliss to build this Mark Two version of the balance.
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10.
Kibble balance originating from the National Physical Laboratory was transferred to the National Research Council of Canada in 2009, where scientists from the two labs continued to refine the instrument.
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11.
Kibble balance avoids the problems of measuring B and L in a second calibration step.
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12.
Kibble balance is constructed so that the mass to be measured and the wire coil are suspended from one side of a balance scale, with a counterbalance mass on the other side.
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13.
The current Kibble balance experiments are equivalent to measuring the value of the conventional watt in SI units.
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