Anglicky v odborných předmětech "Support of teaching technical subjects in English “

1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Mechanic - electrician Topic: Electric measurement the 2nd. year Measuringdevices 1 Prepared by: Ing. Jiří Smílek Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

2. Measuring Devices • Electrical measurements - a task: • For electrical measurements we find the size of electrical quantities • such as voltage, current, power, resistance, inductance, capacity, frequency, etc. • electrical measurements we verify or check properties • electrical sources, appliances, telecommunication facilities, electrical grids and lines.

3. Measuring devices - method • Types of measurement: • Measurement – specifies the numeric value of the measured quantity • Counting - determines the number of events of the same type • Testing – determines whether the sample has the prescribed properties • Calibration – determines the deviation from the correct data • Adjustment(offset) - offset the MP in order to minimize data which was different from the correct values • Calibration- the official procedure for verifying the accuracy

4. Measuring devices - method • Measuring methods • Direct measuring method • size of the measured values ​​read directly on the appropriate measuring device • Such as voltage, current • indirect measuring method • from other measured values, we calculate the size of the desired quantities • Such as resistance R=U/I, power P=U.I

5. Measuring devices - methods • Measuring methods according to function: • deviation • size of the measured quantity is determined by the size of the deflection of the measurement devices hands • zero • measured quantity is subject to settlement (electrical balance), such as measuring bridge

6. Measuring devices - methods • Measuring method according to the nature: • substitution • an unknown measured element is replaced with the element of known parameters • Parallel connection • Measured current • comparative • effects of an unknown element are compared with the effects of an element with known parameters • Series connection • Measured voltage

7. Measuring devices - errors • Causes of errors according to the cause origin • imprecision of the measurement devices • imprecision of measuring methods - correctable • influence of the environment • Observer reading • Types of errors according to the manner of occurrence • permanent (continuous)- device, the method • random – environment, human • Error measuring:

8. Measuring devices - errors • Error measuring: • Nature of errors - deviations • Difference between the measured and actual values • Δm = M - S • Distribution • Absolute - in units of the measured quantity • Relative - expressed in % • δm= Δm/M . 100 • Limit • deviation from the nominal value ±%

9. Activities for students – questions • Write what is the subject of electrical measurement • Name some kinds of measurements • Name the methods of measuring which you know • Name the methods of measuring which you know according to the function • Name the methods of measuring which you know according to the nature

10. Activities for students – questions • Name the causes of errors • Describe what constitutes an error • Write a formula • Name the types of errors • Write a formula • Write a formula • Write a formula

11. Bibliography • Mužík, J. Management ve vzdělávání dospělých. Praha: EUROLEX BOHEMIA, 2000. ISBN 80-7361-269-7. • Operační program Vzdělávání pro konkurenceschopnost, ESF 2007 – 2013. • Dostupné na: http://www.msmt.cz/eu/provadeci-dokument-k-op-vzdelavani-pro-konkurenceschopnost • Učebnice Elektrická měření – Ing. Pavel Vylegala, SŠE Ostrava, 2006 • Učebnice Elektrické měření – SNTL, 1981 • Elektrotechnika - Laboratorní cvičení pro bakalářské studium - Doc. Ing. Miloš Hammer, CSc.