Since the discovery and implementation of photovoltaic cells our world has been revolutionized by this renewable energy source. Solar Panels convert sunlight into DC electricity. The more sunlight the solar panel is exposed to, it results in the electrons in the solar panel to be “excited” more aggressively, thus resulting in a higher voltage. Many companies and home owners have turned to solar panels to power several appliances being used throughout the building/house. Although solar panels are a huge investment, in the long run they become economically beneficial. During our Freshman Seminar class on October 28, we performed a photovoltaic experiment. During this experiment we measured the voltage output of a small solar panel while changing the height of the light source and the color filter above the solar panel. We used a NXT microcontroller and a voltage probe in order to collect data through a Labview prewritten code. A copy of the code can be seen below.

 

The first task of the experiment that we tested was determining the relationship between distance and voltage output. It is important to remember that as the distance between the light source and the solar panel increase, the light intensity decreases because the photons spread out more with greater distance. We tested this by using a flashlight (in my group we used a iPhone) to serve as our sunlight. We changed the distance between the light source and the solar panel during each trial. We did three trials, each having a distance of 1 cm, 5 cm, and 10 cm respectively. If you look at the graph below, you can conclude that the relationship between light intensity and voltage output is linear. Both variables are inversely proportional to each other. As the distance increases the voltage output will decrease. Our coefficient of determination was 0.9062 thus proving there is a obvious correlation between distance and voltage output.

 

 

 

The second task of the experiment that we tested was discovering how a colored filter affects the voltage output, while keeping the distance constant. We used a green, red, and purple/blue clear transparent filters. We compared the voltage output of each filter to the voltage output with no filter. As can be seen in the bar graph below, as the color depth got darker, the voltage output was getting lower. This is a result of the darker colors absorbing more light and allowing a smaller amount of light through it.

 

 

 

Overall this activity was extremely enjoyable and very educational. This activity connects directly to renewable energy sources such as solar panels. As we observed as the light intensity increases the voltage output increases simultaneously. Solar panels with tracking systems that tilt/rotate the solar panel towards the sun are applying the very basic observation we saw in the experiment. If the solar panel is exposed to the maximum light intensity available it will output the most voltage it can at that moment.