52
A. Shah
Fig. 3.14 To calculate the basic equations governing the operation of a solar cell is, indeed, no
simple task. Courtesy Dji-illustrations, Neuchâtel
3.4.4 Equivalent Circuits for the Solar Cell
1. Basic equivalent circuit
The basic equivalent circuit for all solar cells is given in Fig. 3.15a. It corresponds
to (3.8) and consists merely of a diode D and a photo-current (density) source J ph .
This equivalent circuit is not of any practical use.
2. Standard equivalent circuit
To arrive at the standard solar cell equivalent circuit, which is used universally for
(almost) all solar cell work, one has to add two elements to the basic equivalent
circuit of Fig. 3.15a:
(a) A series resistance R series , which stands mainly for the Ohmic losses in the
contacts and wiring;
(b) A parallel resistance R p , which represents two very different effects: