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 IV 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 IV 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 IV curve. Figure shows rectangular corresponding to area of power.
 The power is zero at open circuit V_{oc} and short circuit current I_{sc} points. The maximum power on the curve is called as maximum power point or MPP. The maximum power point corresponds to V_{MPP} and I_{MPP} shown on the I – V curve. The operating maximum power point generates most possible power at given irradiance conditions.
P_{MPP} = V_{MPP}
× I_{MPP}
Circuit Diagram
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 I_{SC} = _____________
Open circuit condition
 Make the ammeter circuit open circuited and measure voltage across solar cell
 It is open circuit voltage V_{oc} = ____________
 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 shortcircuited condition is zero.
 The point corresponding to V_{m} and I_{m} 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 

V_{oc} 
0 
0 
2 

0 
I_{sc} 
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.
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