Question

The voltage stabilization is effective when there is a minimum Zener current. The Zener diode must be always operated within its breakdown region when there is a load connected in the circuit. Similarly, the supply voltage V_s must be greater than V_z .

Answer 1

A Zener diode is operated in the breakdown region. There is a minimum Zener current, I_zr , that places the desired operating point in the breakdown region. There is a maximum Zener current, I_zM , at which the power dissipation drives the junction temperature to the maximum allowed. Beyond that current the diode can be damaged. Hence, the supply voltage must be greater than V_z and the current-limiting resistor must limit the diode current to less than the rated maxi mum, I_ZM.