Lab Report -RC Circuit- Physics 1402 Describe and perform an experiment to deter

Question

Lab Report -RC Circuit- Physics 1402

Describe and perform an experiment to determine internal resistance of the digital multi meter.

Your lab report will be graded following the rubric. Use paragraph form rather than bullets.

Introduction/Hypothesis 20p

Formulate what you expect the experiment to show.

Identify the measurable quantities in your experiment.

Procedure 30p

Describe what you did and how you did it, what equipment you used (include pictures, diagrams).

Write down equations you used.

Data(results) 20p

Present the observations and the data collected.

Present the data in a table. Draw figures, diagrams graphs (using Excel).

Conclusions 30p

Explain what your data shows and what your interpretation of the results is.

Discuss where and what could influence the accuracy of the data (sources of errors).

Explanation / Answer

Introduction:

Usually DMM or digital multimeters are used to measure different eectric parameters like voltage, current and resistance. The standard tool is a suitable replacement of old analog meter and combines the functions of voltmeter, ammeter and ohmmeter. The internal resistance of DMM is important as the function of DMM while measuring resistance is related to it. DMM measures resistance passing a constant current and checking the voltage drop across it. Next it use V=IR to get the result. Therefore the current passing is dependent on the range on internaal resistance. In this experiment the internal resistance of a DMM is measured using an external resistance and votage difference for the same.

Procedure:

To simplify the prcedure the experiment considers an expression as follows:

DMM internal resistance =[DMM measured voltage*magnitude of external resistane]/(input voltage- DMM measured voltage)

To complete the experiment we need a resistance of 1 megaohm and 1.5v battery for input voltage.

first we measure the voltage of battery via DMM; the value will be greater than given vaalue for internal resistance. Next the resistance is measured. Now a circuit is created by connecting voltmeter, resistanceand DMM in series. Again the reading is taken in volts.

Finally using the formula we get the internal resistance.

Data:

data is taken for three times to chheck the internal resistance.

Conclusion:

From the data it is clear that the extra value while measuring only input voltage is thee contribution of the internal resistance and the samee iss measured using a resistance with it in series. In case of series connection the current can move in a single path therefore measurement iss simplified with low risks of errors.

Battery Voltage resistance circuit voltage internal resistance 1.600 1 .801 1.002megaohm 1.5 1.008 .806 1.17megaohm 1.608 1.008 .808 1.0megaohm

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