Mention the use of a Zener diode.

Two Zener diodes ($A$ and $B$) having breakdown voltages of $6\, V$ and $4\, V$ respectively,are connected as shown in the circuit below. The output voltage $V_{0}$ variation with input voltage linearly increasing with time,is given by: $(V_{\text{input}} = 0\, V$ at $t = 0)$ (figures are qualitative).

$A$ Zener diode,having a breakdown voltage equal to $15\,V$,is used in a voltage regulator circuit as shown in the figure. The current through the diode is......$mA$.

$A$ Zener diode with a power rating of $1 \, W$ is to be used as a voltage regulator. If the Zener diode has a breakdown voltage of $5 \, V$ and it has to regulate an input voltage that fluctuates between $3 \, V$ and $7 \, V$,what should be the value of the series resistance $R_s$ for safe operation? (See figure)

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?

$A$ diode has Zener voltage of $10 \text{ V}$ and maximum power dissipation of $0.5 \text{ W}$. The minimum resistance to be used in series with this diode for safety when it is connected to a $25 \text{ V}$ power supply is . . . . . . $\Omega$.