    be a scalar or vector, but vectors must be of same length as all
%      other input vectors.
% * *|nNsVth|* - the product of three components. 1) The usual diode ideal 
%      factor (n), 2) the number of cells in series (Ns), and 3) the cell 
%      thermal voltage under the desired IV curve conditions (Vth).
%      The thermal voltage of the cell (in volts) may be calculated as 
%      k*Tcell/q, where k is Boltzmann's constant (J/K), Tcell is the
%      temperature of the p-n junction in Kelvi