In the following circuit,the reading of the ammeter will be (Take Zener breakdown voltage $= 4 \ V$) (in $mA$)

$A$ Zener diode is used as:

If the current in the Zener diode is five times the current in $R_1$ and the breakdown voltage of the diode is $6 \text{ V}$,find the value of $R$.

The figure represents a voltage regulator circuit using a Zener diode. The breakdown voltage of the Zener diode is $6\,V$ and the load resistance is $R_L = 4\,k\Omega.$ The series resistance of the circuit is $R_i = 1\,k\Omega.$ If the battery voltage $V_B$ varies from $8\,V$ to $16\,V,$ what are the minimum and maximum values of the current through the Zener diode?

The following diagram shows a Zener diode as a voltage regulator. The Zener diode is rated at $V_Z = 5 \text{ V}$ and the desired current in the load is $5 \text{ mA}$. The unregulated voltage source can supply up to $25 \text{ V}$. Considering the Zener diode can withstand four times the load current,the value of resistor $R_S$ (shown in the circuit) should be . . . . . . $\Omega$. (in $\text{ } \Omega$)

$A$ Zener diode with a Zener voltage of $30 \text{ V}$ is connected in a circuit as shown in the figure. The maximum current through the Zener diode is: (in $\text{ mA}$)