How the angle of a solar cell affects its output.

Knowledge

Before I started to plan my experiment I did some research into the subject to decide what the best way was to carry out my experiment. I was given a choice of two experiments to choose from. One was to see how the intensity of the light affected the power output of the solar cell. However I chose to test how the angle of the solar cell to its light source affects the power output of the solar cell, so the only thing in my experiment that will change will be the angle of the solar cell and everything else will remain as constant as possible The first thing I researched was that if the light source is to close to the solar cell then the reading will be inaccurate as the light will is so close to the solar cell then the angle will not make a difference. Because of this information I will have my light source at a suitable distance away from the solar cell (30 cm). I also found that the solar cell should have the largest power output when it is directly facing the light source; this is because at this point the solar cell has the largest amount of surface area showing the light source and therefore it should in theory at this point generate its maximum energy output. I also discovered that there will not be a significant loss in power output until the solar cell is facing 20º away from the light source and from this point there should start to be quite a dramatic drop in the energy output. Because at this point the cell angle means there is quite a change in the angle of the cell whereas before 20º then the angle would not have really played a major part in the output.

Fair Test

I will make sure that the experiment is fair by making sure the light intensity is equal all the way through the experiment. I will do this by using the same light all the way through the experiment. I will also make sure that the light is at a equal distance away from the solar cell for every result, I will do this by measuring the distance (30cm) and keeping it constant. To get rid of any inaccuracies from other light sources (sun, class lights) I have chosen to carry out my experiment in a dark room where the only light that will be on will be the light that is shining onto the solar cell and the rest of the room will be dark. To make show that my results are accurate and so that I can achieve an accurate average result then I will take 3 readings of every angle that I measure. To make sure that my angle measurements are as accurate as possible I will attach a protractor onto a stand next to the stand which the solar cell is placed. The protractor will remain in that fixed position and the solar cell stand will move until it reaches the correct angle. I will also make sure that I use the same solar cell every lesson because each solar cell has a different about of solar material showing, so for an accurate and fair test I shall use the same solar cell every time. I do not see it necessary to use the same multimeter each lesson as the mutlimeters generally have the same readings. I chose to use multimeters because these are far more accurate then ammeters and voltmeters as you can change the scale on them to suit the amount of power that you have in a circuit.

Prediction

I predict that the amount of light transferred to electricity will decrease the greater the angle increases. I believe this because as stated in my knowledge then as the angle increases the surface are showing to the light is less, this will therefore mean that less light is shining on the cell (or are a weaker gradient) and therefore less light can be transferred into power. But I also believe that after the solar cell reaches the angle of 20 º then the amount of energy transferred will start to decrease at a larger rate. So because of this I predict that the rate at which the output changes will not be directly proportional to the change in angle.

Method

I will first set up my apparatus as shown on the diagram. The aim of the experiment is to find that amount of power that I will receive from the solar cells when it is placed at certain angles. To work this out I will need to use an equation because you can’t take a reading of power from the multimeter, so to find the power I will use the equation

P=IV

I= current

V=voltage

So I will have to take two readings one for the amount of amps generated and another for the amount of current created. This will mean tat in total I will have to take 60 readings, because I am using the angle range of 0ºand 90º and I am taking readings every 10º, for every 10º I am taking 3 measurements for current a 3 for voltage. For every angle I shall turn the white light on and then read the measurements off the multimeter and turn the light off again (this will be repeated 3 times for every angle). I have decided to set the multimeter on the normal setting (maximum 2 volts) when measuring volts. But when I am measuring current I believe that the current will be small so I shall set the multimeter on milliamps when measuring the amps, I will have to stat this on my results table or my power output will be inaccurate. With the results that I get I shall record them into a table and draw a graph to plot the data. I shall then analysis the data and look for any patterns or results that I did not expect to occur.