SKH Li Fook Hing Secondary School
Physics
EM15
Name:_________________________ Class No.:_________
Group No.:_______ Date of Experiment: ________
EM 15 Experiment: Parallel Plate Capacitor
Objective: To familiar the operation of RLC meter and to investigate the parallel plate capacitor.
Apparatus: Digital RLC meter, coil, glass rod, wooden rod, plastic, soft iron rod, steel, capacitor
substitute box, aluminium foil, book, 2 metal plates, a bag of spacers, 1 clip and 1
connecting wire only.
Procedure and results:
(A) Measuring inductance by RLC meter
1. Follow the procedure to set zero for measuring inductance.
2. Measure the inductance of a coil directly. Then, insert different materials inside the coil
and measure the inductance. Tabulate your result:
Coil itself
Coil with
Coil with
Coil with
Coil with
Coil with soft
plastic rod
glass rod
wooden rod
steel plate
iron rod
L/H
PQ1.
Which material will strengthen the inductance most?
(B) Measuring capacitance by RLC meter
1.
2.
3.
Follow the procedure to set zero for measuring capacitance.
Check the capacitance of the capacitors in the capacitor substitute box to familiar the
measuring procedure.
Using the aluminium foil and book to construct a capacitor with steady capacitance
more than 20ηF. You must minimize the use of foil and ask your teacher to certify your
result.
Measured capacitance = ___________________________ Checked by : ____________
(C) Parallel plate capacitor
(I) Effect of plate separation
1. Place 1set of 4 spacers between the metal plates to construct a parallel plate capacitor.
PQ2.
2.
3.
4.
5.
How can you make sure that the plates are parallel?
Measure the capacitance of the parallel-plate capacitor with 1 set of 4 spacers.
Insert 2 sets of 4 spacers to increase the separation of the plates.
Measure the capacitance of the parallel-plate capacitor again.
Place more spacers to increase the separation of the plates and measure the capacitance.
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SKH Li Fook Hing Secondary School
Physics
EM15
Name:_________________________ Class No.:_________
Group No.:_______ Date of Experiment: ________
Tabulate your results:
Separation
1
2
3
d / 1 set of 4 spacers
Capacitance
C/F
Plot a graph of capacitance against
PQ3.
1
.
separation
What is the shape of the graph?
What does the shape of the graph show?
Does the graph pass through the origin? Explain briefly.
(II) Effect of plate overlapped area
1. Measure the length of the plate. Insert
the polythene layer between the
2.
plates.
Measure the capacitance of the
capacitor with the LCR meter.
3.
Changed the overlapped area of the plates to A,
4
3
2
A, A and
A. Measure the
5
5
5
capacitance and tabulate the results:
Area of overlap
A/ x area of whole plate m
1
0.80
0.60
0.40
2
capacitance
C/F
Plot a graph of capacitance against overlapped area.
PQ4.
What is the shape of the graph? What does the shape of the graph show?
Does your graph pass through the origin? Explain briefly.
PQ5.
Why does a load place on the top layer of the plates?
1
PQ6.
Why is an overlapped area of A not measured in the experiment?
5
Questions:
ε A
1. Show that C = o
d
2. Why is the RED/BLACK “Test alligator clips’ provided by the meter’s manufacturer
shorter than the connecting wires in the laboratory?
3. Discuss the sources of error in this experiment.
Reference: Further Physics Book II p.102 – p.105, New Way Physics Book 3 p.64-p.65
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SKH Li Fook Hing Secondary School
Physics
EM15
Name:_________________________ Class No.:_________
Group No.:_______ Date of Experiment: ________
Procedure in measuring capacitance and inductance by RLC meter
(* You must follow the procedure in measuring capacitance and inductance.)
Ensure that the circuit is switched off and de-energized before connecting the test leads.
1.
For the C (Capacitance) measurement
(a) Insert the RED/BLACK “Test alligator clips’ into the ‘L/C Input Terminal 2’.
(b) Zero Adjustment
(i) Before connecting the testing capacitor, the input terminals should be opened.
(ii) The BLUE ‘Zero Button’ should be pushed to set zero. The display will show zero
value.
(c) The testing capacitor should be discharged completely before connecting. The testing
capacitor can be connected to the clips for measurement. If the measured capacitor has
polarity, the ‘+’ pin of the capacitor should be connected to the meter’s ‘+’ terminal.
testing capacitor can be connected to the clips for measurement.
(c) The range of capacitance should start from the lowest range and keep increasing until a
suitable reading is obtained
(d) If display shows ‘-----‘, it indicates an OUT OF RANGE measurement. A proper higher
range should be selected for measurement.
2.
For the L (Inductance) measurement
(a) Insert the RED/BLACK “Test alligator clips’ into the ‘L/C Input Terminal 2’.
(b) Zero Adjustment
(i) Before connecting the testing inductor, the input terminals should be shorted.
(ii) The BLUE ‘Zero Button’ should be pushed to set zero. The display will show zero
value.
(d) The range of inductance must start from the highest range and keep decreasing until a
suitable reading is obtained
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