• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4

# Charging a capacitor at a constant rate

Extracts from this document...

Introduction

Lam Cheuk Ying Regina

F.6C (12)

Date: 25th March, 2010

Title: Charging a capacitor at a constant rate

Objective: To investigate how the charge on a capacitor is related to p.d. applied across it by charging the capacitor at a constant rate.

Apparatus:

• capacitor (electrolytic type) 500 µF
• microammeter 100kΩ
• potentiometer 100kΩ
• clip component holder
• stop-watch
• CRO

Procedure:

1. The circuit was connected up as shown above. The CRO was set to d.c. and the sensitivity was set to 1 V/cm.
2. The time base was set to any high value so that a steady horizontal trace is displaced. The trace was set to the bottom of the screen.
3. The capacitor was shorted out by connecting a lead across it and the 100kΩ

Middle

Q=CV

If a capacitor is charged up at a constant rate, i.e., where I is a constant,

Then  is also constant.

Hence the potential difference across the capacitor increases linearly with time.

Measurements:

Conclusion

V.From the graph, the slope of the straight line = (5-1)V/(40-8)s= 0.125Vs-1

since

0.125 = 80µA/C

C=6.4 X 10-4CV-1

• Sources of errors:

- There is leakage of charge from the capacitor.

- Error in keeping the constant current.

- There is internal resistance of the cell.

- Non-zero value of variable resistance when it is set "minimum".

Conclusion:

By charging the capacitor at a constant rate, the charge on a capacitor is directly proportional to p.d. applied across it

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics section.

## Found what you're looking for?

• Start learning 29% faster today
• 150,000+ documents available
• Just £6.99 a month

Not the one? Search for your essay title...
• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month

# Related AS and A Level Electrical & Thermal Physics essays

1. ## Experiment: Decay of Charge in a Capacitor

4 star(s)

16.14 16.16 16.04 16.11 64.66 65.02 64.78 64.82 15 23.05 23.01 22.86 22.97 92.72 92.39 92.69 92.60 10 32.83 32.60 32.57 32.67 131.44 131.61 131.91 131.65 5 48.17 48.10 48.01 48.09 193.50 192.87 193.94 193.44 Table 2 Table 2 shows the data obtained in procedure 8.

2. ## Investigating the Capacitance of a Parallel-Plate.

proportional to plate separation, current is directly proportional to the length of the plates. We also verify that the relative permittivity is equal to the ratio of current when having a dielectric in between the plates and that when having no dielectric.

1. ## Characteristics of Ohmic and Non Ohmic Conductors.

lit room and then the readings of current and the resistance can be taken. As we know the resistor has to be connected between the points X and Y. The following tables have to be drawn. Brightly lit Voltage (Volts)

2. ## Plotting the decay curve of charge in a capacitor

Since the reaction time of human beings is about 0.2s, it may cause the error in the experiment, and the reaction time of humans directly affect the experimental results. Secondly, the experiment involves measurement error. The apparatus for measurement is not enough, for example, we just record the time correct to the nearest 1 s for using the stop watch.

1. ## Objective To investigate the relationship between the charge on a capacitor and the ...

across it decreases. The variation is linear. When a capacitor is charged by connecting it to a battery or other dc power supply, the current in the circuit gradually falls to zero. The rate at which this happens depends on both the capacitance of the capacitor and the presence of any resistance in the circuit.

2. ## Investigating the Smoothing Effect of a Capacitor on a Resistive Load

To overcome this error, there are some ammeters designed with a mirror helping to ensure that such errors do not occur which I could have used. Zero errors are also common with ammeters. I made sure that the ammeter had been zeroed in order to get fair and reliable results.

• Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to