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GateWay CC
PHY101 Physics Lab:
BASIC ELECTRICITY
Purpose
The purpose of this lab is to:
Part I – Use the voltmeter to measure the voltage of batteries connected in series, parallel or
combinations of both
Part II – Use the ampermeter to measure current in a single loop circuit
Part III - Determine the relationship between voltage, current, and resistance in a single loop
circuit.
Part I: Measuring battery voltage using V-meter
Please go to: http://www.gwc.maricopa.edu/class/phy101/simulation/elec/index1.htm
Using Voltmeter (device that measures voltage) measure the voltage of several batteries.
Connect the voltmeter across the single battery, batteries connected in series, or parallel
connected batteries. You will use batteries with nominal voltage 1.5 V. The actual battery
voltage may be lower than this due to the age of the battery. Computer simulation will randomly
generate the actual battery voltage for each student. Batteries connected in series, have the
positive terminal of one cell connected to the negative terminal of another battery. This will
increase the overall voltage. If two 1.5 V batteries are connected in series, the overall voltage is
increased to 3.0 V. Batteries connected in parallel have their like terminals connected together.
The overall voltage remains the same. If two 1.5 V batteries are connected in parallel, the
overall voltage would still be 1.5 V. Batteries may also be connected in a series/parallel
combination. Batteries are connected in series in order to increase the total voltage, and in
parallel to increase the battery capacity.
When you connect the battery cells in series, you can use any two, three or more batteries.
When you connect the battery cells in parallel you need to use only batteries with the same
nominal voltage – two, three, or more. Connecting batteries with different nominal voltage may
produce dangerous situations. Connect the circuits in Figures 1 – 5, and measure and record in
your notebook reading from the voltmeter. Follow the directions in the simulation.
Figure 1. Voltage measurement of single battery
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Figure 2. Two batteries connected in series
Figure 3. Three batteries connected in series
Figure 4. Two batteries connected in parallel
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Figure 5. Two batteries connected in parallel and the third one in series
Collected data from the simulation must be recorded in the table below.
Voltage
Nominal
Voltage
V
Single Cell – Figure 1
Two cells connected in series – Figure 2
Three cells connected in series – Figure 3
Two cells connected in parallel – Figure 4
Two cells connected in parallel and the
third one in series – Figure 5
Recorded
Voltage
V
Absolute
Difference
V
%
Difference
%
2.0
4.0
6.0
2.0
3.0
The absolute difference is:
Absolute Difference  Nominal Voltage  Measured Voltage
The % difference is: ((Nominal Voltage – Measured Voltage)/Measured Voltage)*100%
% Difference 
Nominal Voltage  Measured Voltage
 100(%)
Measured Voltage
Part II: Current measuring using Ampermeter
Please go to: http://www.gwc.maricopa.edu/class/phy101/simulation/elec/index2.htm
In a Part I, we used voltmeter to measure the potential difference (voltage) across two battery
terminals. Ampermeter, on the other hand, measures the flow rate of charge as electrons move
through the circuit – conductors. Therefore Ampermeters is inserted right into the flow of charge
– in series.
Connect the circuit in Figure 6, and take several current readings on the A-meter by changing
the value of the Resistor R. Record the values of Resistor R and current readings in the table
bellow. Follow the directions in the simulation.
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Figure 6. Current Measurement using Ampermeter
Battery
Voltage
V
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
Resistor
R
Ohm
10
20
50
100
150
200
300
400
500
Current
A-meter Reading
A
Current
A-meter Reading
mA
Using the current and resistor data, graph the variation of current with resistor. On the y – axis,
show the current values in mA and on the x – axis show resistor data in Ohms.
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Part III: The relationship between Voltage, Current, and
Resistance
Please go to: http://www.gwc.maricopa.edu/class/phy101/simulation/elec/index3.htm
To determine the relationship between the three basic concepts in electricity: voltage, current,
and resistance we are going to use a single loop circuit shown in figure 7.
Figure 7. Relationship between voltage, Current and Resistance in a single loop
The relationship between current, voltage, and resistance is tested by different values of
voltage, different values of resistance, and measuring the resulting current through the loop.
Numerical data will then reveal the relationship between them. Follow the directions in the
simulation.
Procedure:
1.
2.
3.
4.
5.
6.
Set the nominal battery voltage at 2 V.
Set the value of R = 10 Ohms.
Record the voltage across the resistor (voltmeter).
Measure the current through the loop (ampermeter).
Repeat steps 2, 3, and 4 for nominal battery voltages of 4 V, 6 V, 8 V, 10 V, and 12 V.
Repeat steps 1, 2, 3, 4, 5 for values of the resistance R = 20 Ohms, R = 50 Ohms, and R
= 100 Ohms.
7. Plot a graph for relationship between Voltage and current by plotting the voltage data on
the y axis, and current data (in mA) on the x axis for R = 10 Ohms
8. Plot a graph for relationship between Voltage and current by plotting the voltage data on
the y axis, and current data (in mA) on the x axis for R = 50 Ohms
9. Plot a graph for relationship between Voltage and current by plotting the voltage data on
the y axis, and current data (in mA) on the x axis for R = 100 Ohms
10. Each graph represents a straight line. Use the slope formula from algebra, when two
points on the line are given, to find he slope of each line.
m
y 2  y1
x  x1
11. Slope of the R = 10 Ohms line is:______________ units ____________
12. Slope of the R = 50 Ohms line is:______________ units ____________
13. Slope of the R = 100 Ohms line is:______________ units ___________
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Record all the data in a table below.
Nominal
Battery
Voltage
V
2.0
4.0
6.0
8.0
10.0
12.0
2.0
4.0
6.0
8.0
10.0
12.0
2.0
4.0
6.0
8.0
10.0
12.0
Resistor
R
Voltage
V – m Reading
Current
A-meter Reading
Current
A-meter Reading
Ohm
10
10
10
10
10
10
50
50
50
50
50
50
100
100
100
100
100
100
V
A
mA
Resistance R = 10 Ohms
Resistance R = 50 Ohms
Resistance R = 100 Ohms
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