Question $3(15$ marks$)$

a$-$Sketch an equivalent circuit of a PV cell.

b$-$What is the short$-$circuit current and open$-$circuit voltage of a PV cell and when do they occur? Verify your answer using a neat sketch

c $-$What is the role of a p$-$n junction in a PV cell?

d$-$A single PV module supplies power to a resistive load. Hourly I$-$V curves for the PV module during one day are provided, along with the I$-$V curve for the resistance. Each I$-$V curve applies for one hour $($e$.$g$.,$ the $"8$ A$.$M$."$ curve applies from $7$:$30$ A$.$M$.$ to $8$:$30$ A$.$M$.).$

a$.$ Find the resistance of the load.

b$.$ Estimate the energy delivered to the load during the day.