Download Capacitor Circuit Investigation Name Hour ______ Purpose: Use

Capacitor Circuit Investigation
Name _________________
Hour _________
Purpose: Use this simulation to observe changes that occur in a circuit as time passes.
a. Observe changes in the current during charging and discharging.
b. Observe changes in the voltage across a resistor during charging and discharging.
c. Observe changes in the voltage across a capacitor during charging and discharging.
d. How does placing more than one capacitor affect voltage drops and charge stored in a circuit?
Part 1
a. Go to the wiki page tinyurl.com/marentette-wiki. Click on the link for today’s date.
b. Click on the 1st Simulation.
c. Select load (click on Ok) and navigate to the T drive/ Marentette/Hand Out find the file I stored as
Single Capacitor Simulation. It should look like the screen picture shown below but missing the two
voltage charts.
d. Select Voltage chart and drag the red and black leads so that it reads the voltage across the resistor. (as
shown in picture below)
e. Select Voltage chart and drag the red and black leads so that it reads the voltage across the capacitor.
(as shown in picture below)
f. Select Current chart and drag the lead so that it reads the current through the resistor.
g. Charge the capacitor by closing the switch on the left.
time
Capacitor Voltage
Resistor Voltage
1. Sketch the graphs of Voltage vs. Time for the resistor and the
capacitor below (after closing the switch).
time
Answer questions by circling or underlining the best answer
2. What happens to the current through the circuit as time goes on and the capacitor charges?
Increases linearly/ increases at a nonlinear rate/decreases linearly/ decreases at a nonlinear rate /
3. What happens to the amount of charge on the capacitor as time goes on and the capacitor
charges?
Increases linearly/ increases at a nonlinear rate/decreases linearly/ decreases at a nonlinear rate/
time
Capacitor Voltage
Resistor Voltage
4. Now discharge the capacitor by opening the switch on the left and closing the switch on the right.
Sketch the graphs of Voltage vs. Time for the resistor and the capacitor below.
time
Current
5. Sketch the graph of Current vs. Time for the resistor and the capacitor below (as they discharge).
time
6. What happens to the current through the circuit as time goes on and the capacitor discharges?
Increases linearly/ increases at a nonlinear rate/decreases linearly/ decreases at a nonlinear rate/
7. What happens to the amount of charge on the capacitor as time goes on and the capacitor
discharges?
Increases linearly/ increases at a nonlinear rate/decreases linearly/ decreases at a nonlinear rate /
8. Calculate the total charge stored on the capacitor when it is fully charged. Right click on the
capacitor to find its capacitance. Use the voltmeter to find the voltage drop across the capacitor
after a long time. Calculate the charge on the capacitor.
Select load and navigate to the Teacher’s Directory to find the file I stored as
Capacitor Simulation II. It should look like the screen picture shown below.
a. Place a voltage chart across each capacitor.
b. Place a current chart to see the current through the capacitors.
c. Click on Voltmeter.
d. Close the left hand switch to charge the capacitors.
9. How does the voltage drop across each capacitor
compare for every instant of time?
The two capacitors always have the same voltage drop/ the
two capacitors always have different voltages/ the two
capacitors sometimes have different voltages
10. Check the value of the battery’s voltage by right
clicking on it. How does the voltage drop across each
capacitor compare to the voltage across the battery after
they are charged up?
The battery has the same voltage drop as each capacitor/
If you add up the capacitors’ drops you get the battery voltage/ There is no relationship at all between the
voltage of the battery and the voltages of the capacitors
11. Calculate the total charge in the circuit. Right click on the capacitors to find their capacitance.
Use the voltmeter to find the voltage drop. Calculate the charge on each capacitor. Add the
charges together to determine total charge.
12. Does it appear that placing two capacitors in a circuit with one pathway (series circuit) for charge
increases or decreases the total amount of charge stored?
More total charge is stored with two capacitors in series than a single capacitor in series with a battery/
Less total charge is stored with two capacitors in series than a single capacitor in series with a battery/
Same total charge is stored whether there are two capacitors in series with a battery or if there is a single
capacitor in series with a battery
13. Discharge the capacitors by opening the left switch and closing the right switch. Increase the
capacitance of the top capacitor (right click on it). Repeat the charging process. How does the
voltage drop across each capacitor compare?
The Larger the capacitor’s capacitance the larger the voltage/ The Larger the capacitor’s capacitance
the smaller the voltage/ Voltage is independent of capacitance
14. Fill in the chart below after allowing the capacitors to fully charge.
a. Use the voltmeter to measure the voltage across each capacitor.
b. Calculate the charge on each capacitor.
c. Fill in the voltage of the battery for total voltage. The total charge is the charge on one
capacitor (it’s the charge that left the battery). Calculate total capacitance.
Capacitance
Voltage
Charge
Top Capacitor
Bottom Capacitor
Total
15. What is the relationship between the size of the capacitor and the amount of charge it stores?
The Larger the capacitance of a capacitor the larger the charge stored/
The Larger the capacitance of a capacitor the smaller the charge stored/
Capacitance is independent of charge stored
Select load and navigate to the Teacher’s Directory to find the file I stored as
Capacitor Simulation III. It should look like the screen
picture shown below.
a.
b.
Place a voltage chart across each capacitor
Close the bottom switch to charge the capacitors.
16. How does the voltage drop across each capacitor
compare for every instant of time?
The two capacitors always have the same voltage drop/ the
two capacitors always have different voltages/ the two
capacitors sometimes have different voltages
17. Check the value of the battery’s voltage by right clicking on it. How does the voltage drop across
each capacitor (use the voltmeter) compare to the voltage across the battery?
The battery has the same voltage drop as each capacitor/
If you add up the capacitors’ drops you get the battery voltage/
There is no relationship at all between the voltage of the battery and the voltages of the capacitors
18. Calculate the charge stored on each capacitor after a long time. Add the charges together to find
total charge.
19. Does it appear that placing two capacitors in a circuit with multiple pathways (parallel circuit) for
charge increases or decreases the amount of charge stored?
More total charge is stored with two capacitors in parallel than a single capacitor in series with a
battery/
Less total charge is stored with two capacitors in parallel than a single capacitor in series with a battery/
Same total charge is stored whether there are two capacitors in parallel with a battery or if there is a
single capacitor in series with a battery
20. Discharge the capacitors by opening the bottom switch and closing the top switch.
Increase the capacitance of the top capacitor. Repeat the charging process. Fill in the chart below after
allowing the capacitors to fully charge.
a. Use the voltmeter to measure the voltage across each capacitor.
b. Right click on the capacitor to determine its capacitance
c. Calculate the charge on each capacitor.
d. Fill in the voltage of the battery for total voltage. Add the two charges together for total
charge (charge that left the battery). Calculate total capacitance.
Capacitance
Voltage
Charge
Top Capacitor
Bottom Capacitor
Total
21. How does the voltage drop across each capacitor compare?
The Larger the capacitor’s capacitance the larger the voltage/ The Larger the capacitor’s capacitance
the smaller the voltage/ Voltage is independent of capacitance
22. What is the relationship between the size of the capacitor and the amount of charge it stores?
The Larger the capacitance of a capacitor the larger the charge stored/
The Larger the capacitance of a capacitor the smaller the charge stored/
Capacitance is independent of charge stored
Part 2
a. Go to the 2nd simulation on the wiki.
Select the tap Dielectric and select everything on
the right hand side.
b. Select show all charges
c. Place the voltmeter across the capacitor
d. Place the Electric field detector inside
the capacitor
e. Set the battery voltage to 1.5 Voltage.
1. Move the custom dielectric (5 dielectric constant) in and out of
the capacitor by sliding it to the right and left. Answer the following questions for the time
period while the dielectric moves into the capacitor.
a. What happens to the capacitance of the capacitor? Increases/decreases/stays the
same
b. What happens to the charge on the capacitor? Increases/decreases/stays the same
c. What happens to the electric field created by the plate (you may have to click on the
zoom buttons)? Increases/decreases/stays the same
d. What happens to the electric field in the dielectric (you may have to click on the
zoom buttons)? Increases? Increases/decreases/stays the same
e. What happens to the electric field sum? Increases/decreases/stays the same
f. What happens to the voltage? Increases/decreases/stays the same
g. What happens to the stored energy? Increases/decreases/stays the same
2. Fill in the following chart for various dielectrics completely inside the capacitor. Keep the
battery set to a voltage of 1.5 Volts.
Type of dielectric
Capacitance
Plate Charge
Stored Energy
Sum of electric
field
Custom (constant
1)
Teflon
Paper
Glass
3. Fill in the following chart for various dielectrics halfway inside the capacitor. Keep the
battery set to a voltage of 1.5 Volts.
Type of dielectric
Capacitance
Plate Charge
Stored Energy
Sum of electric
field
Custom (constant
1)
Teflon
Paper
Glass
4. Change to custom dielectric (5 dielectric constant), voltage 1.5 voltage and have the dielectric
outside the capacitor. Now click on “disconnect battery. Move the dielectric into the
capacitor. Answer the following questions for while the dielectric moves into the capacitor.
a. What happens to the capacitance of the capacitor? Increases/decreases/stays the
same
b. What happens to the charge on the capacitor? Increases/decreases/stays the same
c. What happens to the electric field created by the plate (you may have to click on the
zoom buttons)? Increases/decreases/stays the same
d. What happens to the electric field in the dielectric (you may have to click on the
zoom buttons)? Increases? Increases/decreases/stays the same
e. What happens to the electric field sum? Increases/decreases/stays the same
f. What happens to the voltage? Increases/decreases/stays the same
g. What happens to the stored energy? Increases/decreases/stays the same