Question

In a zener -regulated power supply a zener diode with $V_z=6$ volt is used for regulation. The load current is to be $4mA$ and the unregulated input is $10$ volt. What should be he value of series resistor $R_s$.if the current through diode is five time the load current ?

Answer 1

$I_{total}=(5\times 4)mA+4mA$
$=24mA$
$V_z=6=I_T{R}_S$
$6=24\times {10}^{-3}Rs$
$R_s=\frac{6}{24}\times {10}^3=2.5\times {10}^2$