How to Graph the I-V Curve of a Silicone Solar Cell With Excel

By Warren Davies

An I-V curve, also known as a current-voltage curve, displays the possible current to voltage combinations that a photovoltaic cell can have. A cell has maximum current but no voltage during a short circuit of its negative and positive terminals. It has maximum voltage but no current during a circuit break. Using a variable resister, you can take readings of a cell's output at every condition between these two extremes, then use this data and Microsoft Excel to create an I-V curve, for an at-a-glance look at the conditions between these two extreme states.

Step 1

Load Excel and open a blank worksheet.

Step 2

Add titles to the top of three columns which will represent your data. Type “Current” in cell A1 and “Voltage” in cell B1.

Step 3

Enter the voltage and current data into these two columns, below their respective headers. Start with the data for a current reading of zero -- the current values should increase as you move down the column, while the voltage values should decrease.

Step 4

Select all your data by clicking and holding the left mouse button on cell A1, then dragging the pointer down to the last cell of data in column "B."

Step 5

Click the “Chart” icon, then in “Chart Type” click the “Line” icon. Select the line graph that does not place data points on the graph, as this makes the curve easier to see. Click “Next,” then click the “Data series in columns” radio button. Click “Next,” then click the icon next to the the “Range for Y-Values” text box. Select all your data in column "A," then click the icon again. Do the same for the “Categories” text box, only this time select the data in column "B." This places Voltage on the "Y" axis and Current on the "X" axis.

Step 6

Click “Next.” In the “Title” text box, give the chart a suitable header, and use the “Subtitle” text box if you wish to have a subheader. Type “Voltage” into “X Axis,” “Current” into “Y Axis,” and uncheck the “Legend” check box. Click “Finish” when you're done.