Download Current in a Series Circuit

Activity 24A
PS-2826
Current in a Series Circuit
Electricity: current, parallel circuit
Qty
1
1
1
2
Equipment and Materials
PASPORT Xplorer GLX
PASPORT Voltage-Current Sensor
CASTLE Kit
‘D’ Cell
Part Number
PS-2002
PS-2115
EM-8624A
PI-6602
Purpose
The purpose of this activity is to determine the relationship between current 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 current through the
circuit 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
Use a PASPORT Voltage-Current Sensor to measure the current
through a series circuit that has one, two and then three light bulbs.
Use the Xplorer GLX to record and display the current. Compare the
current for one, two, and three light bulbs.
Fig. 1: Series circuit
Prediction
How would the current through a series circuit change as more light bulbs are added to the
circuit?
Safety Precaution
•
Follow all directions for using the equipment.
Physics with the Xplorer GLX
© 2006 PASCO
p. 175
Activity 24A
Current in a Series Circuit
PS-2826
Procedure
GLX Setup
1.
Connect a PASPORT Voltage-Current Sensor to a
sensor port on the top of the GLX and then turn on the
GLX ( ).
•
The GLX displays a Graph screen of Current (A)
versus Time (s).
2.
Press
to go to the Home screen. Use the arrow
keys to select Digits and press
to activate your
choice.
3.
In the Digits screen, press
to activate the
measurement name. Use the arrow keys to select
‘Voltage’ and press
to open the measurement
name menu.
4.
Select ‘Clear Input’ and press
choice.
Fig. 1: Select ‘Digits’
to activate your
Equipment Setup
1.
Put two D cells into the battery holder (from the
CASTLE Kit). Put a round light bulb in each of three
lamp sockets.
2.
Set up a circuit with one light bulb, the
Voltage-Current Sensor, and the voltage
source as shown.
•
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: Select ‘Clear Input’
Record Data
•
NOTE: The procedure is easier if one person
handles the equipment and a second person
handles the Xplorer GLX.
Fig. 3: Equipment setup
Physics with the Xplorer GLX
© 2006 PASCO
p. 176
Activity 24A
Current in a Series Circuit
PS-2826
Series Circuit: One Light Bulb
1.
Connect the clip to the voltage source to complete the
circuit. Observe the brightness of the bulb.
2.
Press Start (
) on the GLX to measure the signal
from the Voltage-Current Sensor.
3.
Record the current through the circuit in the Data
Table in the Lab Report section.
4.
Press
to stop data recording. Disconnect the clip
to the voltage source to open the circuit.
Fig. 4: Record data
Series Circuit: 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.
Press Start (
) on the GLX to measure the
signal from the sensor.
4.
Record the current through the circuit for two
light bulbs in the Data Table.
5.
Press
to stop data recording. Disconnect
the clip to the voltage source to open the circuit.
Series Circuit: Three Light Bulbs
1.
Connect a third light bulb in series with the
other light bulbs in the circuit.
2.
Connect the clip to the voltage source to
complete the circuit. Record the apparent brightness of
the three bulbs.
3.
Press
4.
Record the current through the circuit for three light
bulbs in the Data Table.
5.
Press
to stop data recording. Disconnect the clip
to the voltage source to open the circuit.
Fig. 5: Two bulbs in series
to measure the signal from the sensor.
Analysis
Examine your recorded current data and answer the questions
in the Lab Report.
Fig. 6: Three bulbs in series
Physics with the Xplorer GLX
© 2006 PASCO
p. 177
Activity 24A
Current in a Series Circuit
PS-2826
Extension
Repeat the procedure with the resistors included in the CASTLE Kit instead of light bulbs.
Record your results and answer the questions in the Lab Report section.
Physics with the Xplorer GLX
© 2006 PASCO
p. 178
Activity 24A
Current in a Series Circuit
PS-2826
Lab Report – Activity 24A: Current in a Series Circuit
Name ________________________________ Date ___________
Prediction
How would the current through a series circuit change as more light bulbs are added to the
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?
Data Table
Item
Current (A)
One light bulb in series
Two light bulbs in series
Three light bulbs in series
Questions
1.
What did you notice about the brightness of each bulb in series as the second and third
bulbs were added to the circuit?
2.
How did the current for three light bulbs and two light bulbs in series compare to the
current for one light bulb?
3.
How does the current in a series circuit change as you add more light bulbs to the circuit?
Physics with the Xplorer GLX
© 2006 PASCO
p. 179
Activity 24A
4.
Current in a Series Circuit
PS-2826
Do your results support your prediction?
Physics with the Xplorer GLX
© 2006 PASCO
p. 180