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Athens Programme. Athens Programme. Metrology of Electrical Quantities. Laboratory of Preci sion Electrical Measurements Department of Measurements Faculty of Electrical Engineering Czech Technical University in Prague Responsible professor: Prof. Ing. Jaroslav Bohacek, DrSc.
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AthensProgramme AthensProgramme Metrology of Electrical Quantities Laboratory of Precision Electrical Measurements Department of Measurements Faculty of Electrical Engineering Czech Technical University in Prague Responsible professor: Prof. Ing. Jaroslav Bohacek, DrSc. Phone +420 22435 2220 E-mail bohacek@fel.cvut.cz http://measure.feld.cvut.cz/...
William Thomson, Lord Kelvin I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it … … but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind.
Brian W. Petley Far from being a dull area of science, high-precision measurements are an increasingly exciting area in which to work, for they push theory and experiment to the very limits of which they are capable… If we recall that the rich oil deposits under the North Sea remained unknown until the advent of the very precise geophysical measurements, or that the spin of the electron was inferred from precise spectroscopic measurements, we see more clearly the class of discoveries which can come from precise measurement.
Laboratory visit Course objectives Lectures What is metrology? Previous intro Laboratory demonstrations Please, select some topic above to continue
Laboratory demonstrations • Thompson-Lampard's capacitance standard • Frequency performance of resistance standards • Calibration of capacitance boxes
Course objectives: • to present an overview of modern and perspective methods for precision measurements of electrical quantities, • to demonstrate various techniques used in calibrations of electrical measurement instruments and standards.
Lectures • Lecture 1 • Introduction • Measurement units and measurement standards • Quantum standards of voltage and resistance • Thompson-Lampard's capacitance standard • Equivalent circuits of standard resistors, capacitors and inductors • Resistors with calculable frequency performance • Transfer standards
Lectures • Lecture 2 • Voltage and current inductive ratio devices and optimization of their metrological parameters.
Lectures • Lecture 3 • Methods for precision measurement of dc current and dc voltage • Modern potentiometers • Measurement of voltage, power and energy in audiofrequency range
Lectures • Lecture 4 • Bridges for dc and ac measurements of resistance • Transformer and current-comparator-based capacitance bridges • Metrological applications of the quantum Hall effect (QHE)
What is Metrology? Metrology is the science of measurement.
What is Metrology? Metrology covers three main activities: • The definitionof internationally accepted units of measurement, e.g. the metre. • The realizationof units of measurement by scientificmethods, e.g. the realizationof a metre through the use of lasers. • The establishment of traceabilitychains by determining and documenting the value and accuracy of a measurement and disseminating that knowledge, e.g. the documented relationship between the micrometer screw in a precision engineering workshop and a primary laboratory for optical length metrology.
What is Metrology? Metrology is considered in three categories with different levels of complexity and accuracy: • Scientific metrologydeals with the organisation and development of measurementstandards and with their maintenance (highest level). • Industrial metrologyhas to ensure the adequate functioning of measurementinstruments used in industry as well as in production and testing processes. • Legal metrologyis concerned with measurements where these influence thetransparency of economic transactions, health and safety.
Systematic measurement with known degrees of uncertainty is one of the foundations of industrial quality control and, generally speaking, in most modern industries the costs bound up in taking measurements constitute 10 -15% of production costs.
Laboratory visit: • Czech Metrology Institue • www.cmi.cz • Calibration of digital multimeters • Quantum Hall effect based calibrations of resistance standards
Laboratory of Legal Metrology, CTU Prague See you in Prague!