Zrnescu Estera AnaFacultatea de Inginerie MedicalaGrupa 1424

Msurarea rezistenei electrice prin metode directe

Metodele directe de msurare utilizeaz aparate special construite n vederea msurrii, prin citire direct, a valorii mrimii msurate (ampermetre, voltmetre, ohmmetre, wattmetre etc.). n cazul msurrii elementelor parametrice de circuit, acestea necesit, pentru msurarea direct a R,L sau C, o energie de activare extern, asigurat de o surs de curent continuu (n cazul msurrii rezistenei electrice) sau de curent alternativ (pentru msurarea impedanei). Lanul de msurare specific aparatului respectiv convertete aceast mrime parametric (R,X sau Z) ntr-un curent sau o tensiune electric. Un instrument de msurare indic direct mrimea msurat. Pentru msurarea rezistenei electrice cele mai ntlnite aparate de msurare sunt ohmmetrele, ntlnite, de obicei, n componena multimetrelor analogice i numerice, ca funcii de msurare ale acestora.

Msurri i calculul erorilor pentru Rezistenele EtalonR etalon []Range[u.m.]Rx[u. m.]Rmax [] [%]

101010.02460.000250490.002505

1010010.01780.000700360.007004

101k0.010017k0.005200340.052003

1010k0.00993k0.05019860.501986

10100k0.0092k0.5001845.00184

101M0.000009M5.00018050.0018

100100100.01830.002500370.0025

1001k0.10002k0.00700040.007

10010k0.09995k0.0519990.051999

100100k0.0994k0.5019880.501988

1001M0.000099M5.001985.00198

10010M0.00009M50.001850.0018

100100M0.0001M500.002500.002

10001k1.000009k0.025000180.0025

100010k0.99997k0.06999940.007

1000100k0.9997k0.5199940.051999

10001M0.000999M5.019980.501998

100010M0.001M50.025.002

1000100M0.001M500.0250.002

10001000M0.001M5000.02500.002

1000010k9.99904k0.24998080.0025

10000100k9.9986k0.6999720.007

100001M0.009998M5.199960.052

1000010M0.00999M50.19980.501998

10000100M0.01M500.25.002

100001000M0.01M5000.250.002

100000100k99.9678k2.4993560.002499

1000001M0.09997M6.99940.006999

10000010M0.09998M51.99960.052

100000100M0.1M5020.502

1000001000M0.1M50025.002

10000001M0.999485M24.98970.002499

100000010M0.99976M69.99520.007

1000000100M0.9998M519.9960.052

10000001000M1M50200.502

n tabel: Rx valoarea citit de pe ohmmetruRmax eroare absolut - eroare relativ Exemplu de calcul:

[%]

Pentru Retalon = 10, Range = 10, Rx = 10.02460

%

Afiarea valorii se va face: Retalon [um]Rmax [um]Pentru exemplul de calcul, valoarea va fi: 10 0.0250492