Question

1. In this question we will demonstrate the losses that occur when measuring the J-V relation of a
c-Si wafer with a 2-point-probe measurement setup. We consider a c-Si solar cell with an area
of ?cell = 225 cm2 for which the following specifications are determined by a 4-point-probe
measurement setup: FF = 0.802, ?sc = 40.0 mA⁄cm2, ?oc = 0.600 V, and ?mpp = 0.550 V. In
the case of a 2-point-probe measurement system there is a total contact resistance between the
probes and the cell of ?contact = 0.0100 Ω. For the electrical wiring we have the following:
Total wiring length: ? = 60.0 cm; Diameter: ? = 1.00 mm; Resistivity: ? = 1.70 × 10-8 Ω m.
1.Calculate the current at maximum powerpoint (?mpp) in [A].
2. Calculate the voltage drop at maximum power point (∆?mpp) in [V], caused by the contact
resistance (?contact) and the resistance in the wiring (?wires), in the 2-point-probe
measurement system.
3. How large is this fraction (∆?mpp) compared to the voltage at maximum powerpoint ?mpp
in [%]?
4. What is the voltage at maximum powerpoint (?mpp-measured) that is measured by this 2-
point-probe device in [V]?

answers are:

1. The current at maximum power point is: ?mpp = 7.87 A.
2. The voltage drop ∆?mpp = 0.181 V.
3. That is: ∆?
mpp⁄?mpp = 32.9%.
4. The measured voltage is: ?measured = 0.369 V.

how to solve & get same answers , including question 4.

Answer 1