Thevenin maximum power transfer theorem
here i let X=efficiency*output power and consider a voltage source connected in series with an internal resistance and a load resistance,nRin where n is the value to be find.
efficiency=Pout/Pin=V^2[(nRin)/(Rin+nRin)^2]/V^2(nRin+Rin)=n/(1+n)
output power=v^2(nRin)/(n+1)^2Rin^2)=(V^2/Rin)(n/(n+1)^2)
hence X=n^2/(n+1)^3[V^2/Rin]
differentiate it with respect to n using UV method will finally get
dx/dn=[n/(n+1)^3][2-[3n/(n+1)]]
when dx/dn=0 n=0(rejected) and n=2
so at here, can i say if i take into consideration of power saving and the amount of output power dissipated, taking n=2 will give me what i want? a desirable high efficinecy and high output power.