Snmek 1
Anglicky v odbornch pedmtech"Support of teaching technical subjects in EnglishTutorial: Mechanic - electrician
Topic: Basics of electrical engineering the 2nd. year Measuring the capacityPrepared by: Ing. Ji Smlek
Projekt Anglicky v odbornch pedmtech, CZ.1.07/1.3.09/04.0002je spolufinancovn Evropskm socilnm fondem a sttnm rozpotem esk republiky.
Definition of units of capacity
Measuring capacityThe basic unit - 1 F (farad)1 farad is the capacity of an electric capacitor, which has a voltage of 1V and holds a charge of 1C.Capacitance is:Directly proportional to:the active area Spermittivity Inversely proportional to:the distance between the plates dC= S/d
Slovnk:permitivita
Frazeologie:1 farad je kapacita elektrickho kondenztoru, kter pi napt 1 V pojme nboj 1 C. Kapacita kondenztoru je:pmo mrn obsahu inn plochy Snepmo mrn vzdlenosti desek d2The used method:
Measuring capacityVolt-ampere (Ohms) method applied to the measurements of large impedancesSupply voltage must have a known and constant frequencyInvolvement of a small C
Involvement of a large C
Slovnk:
Frazeologie:Voltamprov (Ohmova) metoda aplikovan na men velkch impedancNapjec napt mus mt znmou a konstantn frekvenci
3Measuring inductanceWe must know:currentvoltage When we dont know the value of the capacity CX we calculate it from basic data from an A-metre and a V-metreCapacitive reactance
Of which we dont know the capacity, the angular frequency will help
Or the help of frequency f
Calculation 1 when an AC current:
Slovnk:Kapacitn reaktance Frazeologie:Musme znt:Hodnotu neznm kapacity CX vypotme na zklad daj A-metru a V-metru z toho neznm kapacita pomoc hlov frekvence nebo pomoc frekvence f4Measuring inductanceWhen measuring it is important that there is an AC current flowing through the circuitIf not, you should make a re-count on a replacement scheme
Phasor diagram
Calculation 2:
Slovnk:Fzorov diagramFrazeologie:Pi men je dleit, aby obvodem tekl stdav proudpokud ne, nutno provst pepoet podle nhradnho schmatu5The used method:
Measuring capacityMeasuring capacity distribution of an electric charge
The measurement procedure:
The capacity of the capacitor C is known and the position I of switch p is charged with a voltage U and a charge Q. Switch the switch to position 2; by an unknown capacity CX connected in parallel to capacity C. The charge is divided into two capacitors and the voltage U is subtracted again from the voltmeter. For the switch appliesIn position 1 - Q = U.C In position 2 - Q = U.Cx + UxCx. Unknown capacity of a capacitor
Slovnk:
Frazeologie:Men kapacity rozdlenm elektrickho nbojeKapacitu kondenztoru C znme a pi poloze I pepnae p jej nabijeme na napt U a nboj Q. Pepneme pepna do polohy 2; tm se neznm kapacita CX pipoj paraleln ke kapacit C. Nboj se rozdl na oba kondenztory a napt U odeteme opt na voltmetru. Pro pepna plat
6Describe how to define a unit of capacity Name for what is the proportional capacity of the capacitor Write what are the requirements for power voltage Draw a circuit for measuringsmall C
large C
Activities for students questions
Slovnk:Frazeologie:Popi jak je definovan jednotka kapacityVyjmenuj emu je mrn kapacita kondenztoruNapi jak jsou poadavky na napjec napt Nakresli zapojen pro men
7Calculate an example:A block capacitor has an unreadable data capacity; we can find out about the circuit with an ammeter. The ammeter showed a current I = 2.76A at a voltage of 230V, 50 Hz
Capacitive reactanceXC =CapacitanceCX =Activities for students questions
Slovnk: Frazeologie:Blokov kondenztor m neiteln daj kapacity; meme ji zjistit obvodu s amprmetrem. Amprmetr ukzal proud I = 2,76 A pi napt 230V, 50 Hz8Muk, J. Management ve vzdlvn dosplch. Praha: EUROLEX BOHEMIA, 2000. ISBN 80-7361-269-7.Operan program Vzdlvn pro konkurenceschopnost, ESF 2007 2013.Dostupn na: http://www.msmt.cz/eu/provadeci-dokument-k-op-vzdelavani-pro-konkurenceschopnostUebnice Elektrick men Ing. Pavel Vylegala, SE Ostrava, 2006Uebnice Elektrick men SNTL, 1981Elektrotechnika - Laboratorn cvien pro bakalsk studium - Doc. Ing. Milo Hammer, CSc.
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