## To Plot the P – V characteristics of solar cell

### Theory

• When the solar cell is connected to load, current flows through load and there should be some voltage across the load. When the solar cell is open circuited, output current is zero. Similarly, when the solar cell is short circuited by wire, output voltage is zero. The output power is product of voltage and current, in both above case power is zero.
• At the end point of I-V curve of solar cell, output power is zero since either current or voltage is zero at these points. The maximum power point (MPP) is the spot near the knee of the I-V curve at which the product of current and voltage reaches maximum.
• Another way to find the location of maximum power point is to draw possible rectangular that will fit beneath I-V curve. Figure shows rectangular corresponding to area of power.

• The power is zero at open circuit Voc and short circuit current Isc points. The maximum power on the curve is called as maximum power point or MPP. The maximum power point corresponds to VMPP and IMPP shown on the I – V curve. The operating maximum power point generates most possible power at given irradiance conditions.

PMPP = VMPP × IMPP

### Instruments / Equipment Required

• Solar cell / Solar panel
• DC milli ammeter
• Voltmeter
• Multimeter
• Patch cords
• Light source

### Procedure

• Place the light source and solar cell in the opposite direction
• Switch on the light source
• Make the light intensity to some fixed value

### Short circuit condition

• Short the load resistance or make the load resistor is equal to zero and measure the current passing through load resistor
• It is short circuit current ISC = _____________

### Open circuit condition

• Make the ammeter circuit open circuited and measure voltage across solar cell
• It is open circuit voltage Voc = ____________
• Vary the load resistor in step from low value to large value / large value to low value and note down the reading of voltmeter and ammeter.
• Plot the graph between power on y axis and voltage on x axis.
• The solar cell power during open circuit and short-circuited condition is zero.
• The point corresponding to Vm and Im on I – V curve is known as maximum power point. OR you can determine maximum power point from observation table.

### Observation table

 Sr. No. Resistor Voltage Current Power = Voltage × Current 1 Voc 0 0 2 0 Isc 0 3 4 5 6

### Graph

The P – V graph is similar to that of shown in below figure.

### Calculation

Power = Current × Voltage

### Conclusion

The power becomes zero at open circuit condition. As the load increases, the power also increases up to maximum point. As the load further increases, the power drops and finally becomes zero at short circuit condition.