Chapter 8 Tutorial

Measurement Fundamentals

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gxu susu yq”

MWW y yu y q sy

°uqu su2 q °uqu°u u yut4 dxu u y

 

squt ru

MWW’s series “ z

. A voltage is developed

across the wiring resistance and current shunt resistance of the internal MWW as shown below.

RS

VS

Vb

R

DMM

 

Vs = Source voltage

Rs = Source resistance

Vb = Burden voltage

R = Current shunt resistance

Error (%) = 100 % x Vb

Vs

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Burden voltage errors, which apply to dc current, also apply to

ac current measurements. However, the burden voltage for ac current is larger due to the internal MWW’s series inductance and the measurement connections. The burden voltage increases as the input frequency increases. Some circuits may oscillate when performing current measurements due to the internal MWW’s series inductance and the measurement connections.

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HP 34970A manual Nm m, Km m