//chapter 3
//example 3.17
//page 110
printf("\n")
printf("given")
Vz=6.2;Pd=400*10^-3;Es=16;
Izm=Pd/Vz
R1=(Es-Vz)/Izm
Pr1=(Izm^2)*R1
Izmin=5*10^-3;
Izmax=Izm-Izmin;
printf("maximum current is %3.4fA\n",Izmax)