Question

In a zener regulated power supply, a zener diode with $V_{z}=6 V$ is used for regulation. The load current is $5\, mA$ and unregulated input is $10\, V$ (as shown). The value of series resistance $(R)$ required is

• A. $130\, \Omega$
• B. $160\, \Omega$
• C. $150\, \Omega$
• D. $240\, \Omega$

Answer 1

Answer: (B)

Voltage drop across series resistance $R$
$\Rightarrow V_{R}=10-6=4\, V$
$R=\frac{V_{r}}{I}=\frac{4}{25 \times 10^{-3}}$
$=\frac{4000}{25}=160\, \Omega$