Download Voltage in a Series Circuit

Activity 23A
PS-2826
Voltage in a Series Circuit
Electricity: voltage, series circuit
Qty
1
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1
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Equipment and Materials
PASPORT Xplorer GLX
Voltage Probe (included with GLX)
CASTLE Kit
‘D’ Cell
Part Number
PS-2002
EM-8624A
PI-6602
Purpose
The purpose of this activity is to determine the relationship between voltage and the number of
light bulbs that are connected to a voltage source in a series circuit.
Background
Light bulbs in a series circuit are connected end-to-end like links in a
chain. If light bulbs are connected in series to a voltage source, what
happens to the brightness of the individual bulbs as more bulbs are
added to the “chain”? What will happen to the voltage across each
individual bulb as more bulbs are added to the circuit?
If one bulb in a series circuit is removed, what happens to the rest of
the bulbs?
Preview
Fig. 1: Series circuit
Use a Voltage Probe to measure the voltage across a voltage source
(‘D’ cells) and the voltage across each bulb in a series circuit. Use
the Xplorer GLX to record and display the voltage. Compare the voltages.
Predict
1.
How will the voltages in a series circuit change as more light bulbs are added to the
circuit?
2.
How will the voltage across the voltage source compare to the total voltage across the light
bulbs in a series circuit?
Safety Precaution
•
Follow all directions for using the equipment.
Procedure
GLX Setup
1.
Plug a Voltage Probe into the voltage input port
on the left side of the Xplorer GLX
and then turn on the GLX ( ). A graph of Voltage (V) and Time (s) will open.
Physics with the Xplorer GLX
© 2006 PASCO
p. 163
Activity 23A
2.
Press
Voltage in a Series Circuit
PS-2826
to go to the Home Screen. Select Digits
(
) and press the Activate key (
) to open the
Digits screen. The Digits screen shows Voltage (V).
Equipment Setup
1.
Put two D cells into the battery holder (from the
CASTLE Kit). Put a round light bulb in a lamp socket.
2.
Use a pair of alligator clip patch cords to set up a circuit
with the light bulb and voltage source.
•
Be careful to connect an alligator clip to the spring
as shown.
3.
Leave one clip disconnected until you are ready to
collect data.
Fig. 2: Digits display
Record Data: One Light Bulb
1.
Connect the ends of the Voltage Probe to the lamp
socket in order to measure the voltage across the
light bulb.
2.
Connect the clip to the voltage source to
complete the circuit. Observe the
brightness of the bulb.
3.
Press Start (
) on the GLX to
measure the signal from the Voltage
Probe.
•
The voltage appears in the digits
display.
4.
Record the voltage across the light bulb
in the Data Table in the Lab Report section.
5.
Move the ends of the Voltage Probe to the
alligator clips that are connected to the voltage
source in order to measure the voltage across
the two D cells.
6.
Record the voltage across the two D cells in the
Data Table in the Lab Report section.
7.
Press
to stop data recording. Disconnect
the clip to the voltage source to open the circuit.
Fig. 3: Equipment setup
Fig. 4: Record voltage across light bulb
Fig. 5: Record voltage across D cells
Physics with the Xplorer GLX
© 2006 PASCO
p. 164
Activity 23A
Voltage in a Series Circuit
PS-2826
Record Data: Two Light Bulbs
1.
Connect a second light bulb in series with the first
light bulb in the circuit.
2.
Connect the clip to the voltage source to complete
the circuit. Record the apparent brightness of the
two bulbs.
3.
Connect the ends of the Voltage Probe to the
second lamp socket in order to measure the
voltage across the second light bulb.
4.
Press Start (
) on the GLX to measure the
signal from the Voltage Probe.
5.
Record the voltage across the second light bulb in
the Data Table in the Lab Report
section.
6.
Next, move the ends of the Voltage
Probe back to the first lamp socket to
measure the voltage across the first
light bulb. Record the voltage across
the first light bulb in the Data Table in
the Lab Report.
7.
Finally, move the Voltage Probe back
to the voltage source and measure and
record the voltage across the batteries.
8.
Fig. 6: Two
Fig
Two-bulb
bulb setup
Fig. 7: Record voltage
Fig
Press
to stop data recording.
Disconnect the clip to the voltage source to open the circuit.
Record Data: Three Light Bulbs
1.
Connect a third light bulb in series with
the other two light bulbs in the circuit.
2.
Repeat the procedure to measure the
voltage across each of the light bulbs
and the voltage across the batteries and
record the voltages in the Data Table in
the Lab Report.
Fig. 8: Three
Fig
Three-bulb
bulb setup
Physics with the Xplorer GLX
© 2006 PASCO
p. 165
Activity 23A
Voltage in a Series Circuit
PS-2826
3.
After recording the voltages, remove the light bulb from the middle lamp socket. Record
what happens to the other two light bulbs.
4.
Press
circuit.
to stop data recording. Disconnect the clip to the voltage source to open the
Analysis
Examine your recorded voltage data and answer the questions in the Lab Report.
Extension
Repeat the procedure with the resistors included in the CASTLE Kit instead of light bulbs.
Physics with the Xplorer GLX
© 2006 PASCO
p. 166
Activity 23A
Voltage in a Series Circuit
PS-2826
Lab Report - Activity 23A: Voltage in a Series Circuit
Name ________________________________ Date ___________
Predict
1.
How will the voltages in a series circuit change as more light bulbs are added to the
circuit?
2.
How will the voltage across the voltage source compare to the total voltage across the light
bulbs in a series circuit?
Data
1.
How bright were the two light bulbs in series compared to the first light bulb?
2.
How bright were the three light bulbs in series compared to the first light bulb?
3.
What happened in the three-light bulb circuit when you removed the light bulb from the
middle lamp socket?
Data Table
One Light Bulb
Voltage Across Light Bulb:
Voltage Across Batteries:
Two Light Bulbs in Series
Voltage Across Light Bulb 1:
Voltage Across Light Bulb 2:
Sum of the Voltages Across Both Bulbs:
Physics with the Xplorer GLX
© 2006 PASCO
p. 167
Activity 23A
Voltage in a Series Circuit
PS-2826
Three Light Bulbs in Series
Voltage Across Light Bulb 1:
Voltage Across Light Bulb 2:
Voltage Across Light Bulb 3:
Sum of the Voltages Across Three Bulbs:
Questions
1.
How did the voltage across the two D cells compare to the voltage across the first light
bulb?
2.
How did the voltage across the two light bulbs in series compare to the voltage across one
light bulb? How did the sum of the voltages across two bulbs compare to the voltage
across the D cells?
3.
What did you notice about the voltage across each light bulb and the total voltage across
all three light bulbs in the third part of the procedure?
4.
What can you say about the voltage in a series circuit?
5.
What happened to the light bulbs when you removed the middle bulb from the socket?
Why?
6.
If all the lights in a house are connected together in series and they are all turned on, what
would happen to the lights when you turn one of them off (or it burns out)?
Physics with the Xplorer GLX
© 2006 PASCO
p. 168