Calibration Services

The value of electromotive force of a saturated standard cell can be measured with the stated Calibration and Measurement Capability (CMC) only if the cell is of high quality and is contained in a temperature regulated enclosure.

Cells without temperature control will be calibrated at a nominal ambient temperature of 23°C.

Electronic voltage reference standards submitted for calibration should have a nominal voltage of 1 V, 1.018 V or 10 V. Additional uncertainty will be added for other values of emf.

 

If the potentiometer under test has its own internal voltage reference and power supply, these will be used, unless they are found to be unstable.

Generally, the calibration procedure recommended in the manufacturer's service manual will be followed.

 

Volt ratio boxes rated up to 1000 V are usually calibrated at rated voltage against the Laboratory's standard.

 

AC voltage standards with fixed output voltages will be calibrated by AC-DC transfer measurements. The calibration will also include measurement of output frequency.

 

Inductive voltage dividers (IVDs) will be calibrated by comparison with the Laboratory's 8-dial IVD, normally at specific frequencies of 400 Hz, 1 kHz and 10 kHz with an input test voltage of 25 V. The calibration normally involves measurement of voltage ratio (magnitude) of the output voltage related to the input voltage of the IVD.

The basic calibration for a single decade IVD will include measurement of voltage ratio for all output settings of the IVD at one test frequency.

The basic calibration for a multi-decade IVD will include measurement of voltage ratio at one frequency for all separate settings of the first and second dials of the IVD. Additionally, measurement will be made with all dials in use to realise the ratios which are multiples of 1/11 to cover the performance of all dials.