Rsample = 300000:1000:400000;
Rshunt = 350000;
Radc = 10*10^9;
Vexc = .1;

for i=1:10
    Rs = Rshunt / (.2*i); 
    Req = (Rs * Radc) / (Rs + Radc);
    Vmeas(i)  = Vexc .* ( Req ./ (Req + Rsample));
end

plot(