Question

A zener diode of power rating \(2~\text W\) is to be used as a voltage regulator. If the zener diode has a breakdown of \(10~\text V\) and it has to regulate voltage fluctuated between \(6~\text V\) and \(14~\text V,\) the value of \(R_{S}\) for safe operation should be ________\(\Omega .\)


Ry —AMW—T————o Unregulate Regulated voltage voltage o

• A. 20.00
• B. 20
• C. 20.0

Answer 1

Answer: (A), (B), (C)

When unregulated voltage is $14\text{V}$ voltage across zener diode must be $V_z=10\text{V}$. So potential difference across resistor must be $\Delta V_{R_s}=4\text{V}$
Given Power rating of zener diode is $P=2\text{W}$

$V_{z}I=2$
$I=0.2\text{A}$

Using Ohms law on Resistor,
$\Delta V_{R_s}=I{R}_s=4$
$R_s=\frac{4}{0.2}=20\Omega$