Snmek 1

Anglicky v odbornch pedmtech"Support of teaching technical subjects in EnglishTutorial: Mechanik - elektrotechnik

Topic: Electric measurementthe 2nd. yearOscilloscope 2Prepared 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.

The oscilloscope measures only the voltage against the ground (earth).

Measurement of DC voltageProcedure :Set the horizontal time axis.Positive voltage - zero horizontal axis at the lowest grid line, Negative voltage zero horizontal axis on the top grid line.The size of deflection read from the screen grid,Grid lattice with centimetre and millimetre divisionsDetermination of the measured voltage deducted length multiplied by the set measure (V/cm) and possibly even evaluate the factor of the measuring probe.Dividing (ratio) reduces the input voltage of the probe and it is also less taxing on the measured object.

Measurements using an oscilloscope

Slovnk:Men stejnosmrnch naptPostup Frazeologie:

2Measurement of AC voltagesAC voltage on the Y-axis deflects the beam up and down alternately. Periodic signal course of timeAperiodic signal- light bandDisplay of measured voltage- current value (e.g. peak) AC signal.Voltage peak peak = difference between the highest and lowest deflection beam traces on the screenVoltage size deducted distance multiplied by the set measure in V/cm.Measurements using an oscilloscope

Slovnk:Neperiodick signl Periodick signl asov prbh okamit hodnotarozdl

Frazeologie:Stdav napt vychyluje paprsek odetenou vzdlenost nsobit nastavenm mtkem stdav nahoru a dolZobrazen menho napt 3Measurement of currentA current waveform can be measured indirectly by measuring the voltage drop caused by resistance in a small currentOhms law appliesI=U/RMeasurements using an oscilloscope

Slovnk:Ohmv zkon

Frazeologie:Prbh proudu lze mit nepmo bytek napt na malm odporu zpsobenho proudem 4Display AC valuesThe input signal is applied to the Y-input and the ground(GND). Timebase is set so that the image was still standing still.Measurements using an oscilloscope

Slovnk: asov zkladna Vstupn signl

Frazeologie: Zobrazen stdavch veliinklidn stl5Measurement of frequencyMeasurement of the length of period and thus the frequency of AC signalSet the fine regulation of the time baseswitch the VARIABLE to the cal. positionSet the time base so that one period of the signal occupies the greatest part of the screen.Set the time base starting threshold (LEVEL) so that the process started at zero voltage.Measuring the length of the period on the screen gridThe calculation of frequencies using the formula f=1/TMeasurements using an oscilloscope

Slovnk: Nastaven Odmen dlky

Frazeologie:Men dlky periody Vpoet frekvence pomoc vzorce

6Measurement of phase shiftTwo AC electrical quantities is best viewed simultaneously on the two-beam or dual-channel oscilloscope. The inputs of both channels are connected to periodic signals (same frequency), for which we want to measure the phase shift.Measurements using an oscilloscope

Slovnk:fzov posunchceme zmitFrazeologie:lze nejlpe zobrazitjsou pivedeny periodick signly

7Imaging characteristicsFor a dual channel oscilloscope switch the second channel to the horizontal deflection system (instead of the time base)Then it is possible to arbitrarily change the scale on both axes.Measurements using an oscilloscope

Slovnk:Zobrazovnvodorovn vychylovac systm

Frazeologie: Pak je mono libovoln pepnout druh kanl

8How does the beam move on the screen when the time base is turned on? What shape is produced by an impulse time base? What is the danger of an idle X or Y amplifier?

Activities for students - Questions

Jak se pohybuje na obrazovce paprsek, je-li zapnuta jen asov zkladna? Po vodorovn oseJak tvar maj impulzy vyrbn asovou zkladnou?asov zkladna je tvoen genertorem pilovch kmit Jak nebezpe hroz pi neinnosti jednoho ze zesilova X, Y? Vyplen stopy na obrazovce9What advantage does a driven starting time base have (triggering)? What is the oscilloscope probe or probe ratio? What is the sampling time (Chopper) of an oscilloscope? For which signal frequencies is an alternating mode used (Alternate)?

Activities for students - Questions

Jakou vhodu m zen spoutn asov zkladny (triggering)?U osciloskopu se synchronizovanou asovou zkladnou dostv genertor pilovch kmit pro kad pilov signl nov spoutc impuls.K emu slou u osciloskopu sonda, nebo pomrov sonda?Dlic (pomrov) sonda sniuje vstupn napt, ale tak mn zatuje men objekt.Co znamen vzorkovac reim (Chopper) u osciloskopu?Rozsekv prbhy signl na mal sti (reim Chopper a po stech zobrazujePro jak kmitoty signl se pouv stdav reim (Alternate)?Pokud maj oba vstupn signly vysok kmitoet, je elektronick pepna nastaven na malou pepnac frekvenci, pi kter jsou oba cel prbhy zobrazovny stdav (reim Alternate s frekvenc asov zkladny)

10Muk, J. Management ve vzdlvn dosplch. Praha: EUROLEX BOHEMIA, 2000. ISBN 80-7361-269-7.WikipediePruka elektrotechnika, Europa 2000

Operan program Vzdlvn pro konkurenceschopnost, ESF 2007 2013.Available at: http://www.msmt.cz/eu/provadeci-dokument-k-op-vzdelavani-pro-konkurenceschopnost

Bibliography

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