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Lab 3-3: Measuring and Calculating Voltage and Current


Lab 3-3: Measuring and Calculating Voltage and Current




Equipment for this lab - per team


1 digital multimeter

3 9 volt batteries and 3 connectors

wire nut connectors

1 breadboard


Three 9 Volt Batteries Connected in Series


Connect the batteries as shown below

For part B of the lab, this configuration will be connected to the breadboard with resistor constructed in the previous lab



Section A: Voltage of Individual batteries and batteries in series and Kirkoff's Law


 1.  Use the digital voltmeter to measure the voltage of the three individual 9 V batteries and record those values below.

     battery 1:______      battery 2:______      battery 3: ______


2.  Use the digital voltmeter to measure the total voltage, in series, of the three 9 volt batteries you measured individually above.  Record the value measured below.


     total voltage: ______


3.  Using the individual measurements in part 1 above and Kirckoff's law, calculate the expected total voltage in series. Show your answer and calculations below.





4.  Compare the measured total voltage from part 2 with the calculated total voltage from part 3 and explain and differences found between measured and calculated voltage.




Section B: Current of Batteries in Series and Kirkoff's Law


1.  Connect the three 9-volt batteries in series to the breadboard containing the resistor used in the previous lab.


2. Measure the current on each side of the resistor and record those values below.


    Current on one side:_____________  Current on other side: ________________


3.  What does Kirchoff's law say about the two readings? Should they be the same?




4.  If there was a difference in the readings, provide an estimate of the reason below.




Section C: Batteries in Series and Ampere's Law


1.  According the Ampere's law, VTotal = ITotalxRTotal


2.  Use the total voltage measured from part A2 above and the total current frm B2 above and compare the calculated resistance (R = V/I) with the value of the resistance from the previous

     lab.  Are they the same? If not, provide an estimate of the reason below.