Question

The diode used in the circuit shown in the figure has a constant voltage drop of $0.5V$ at all currents and a maximum power rating of $100$ milliwatts. What should be the value of the resistor $R$ , connected in series with the diode for obtaining maximum current

• A. $1.5\Omega$
• B. $5\Omega$
• C. $6.67\Omega$
• D. $200\Omega$

Answer 1

Answer: (B)

The current through circuit
$i=\frac{P}{V}=\frac{100\times 10^{-3}}{0.5}=0.2A$
$\therefore$ voltage drop across resistance $=1.5-0.5=1V$
$\Rightarrow R=\frac{1}{0.2}=5\Omega$