Question

Which of the following combinations should be selected for better tunning of an LCR circuit used for communication?

• A. $R = 20\ \Omega\text{, L } = \text{ 1.5 H, C } = \text{ 35 }\mu F$
• B. $R = 25\ \Omega\text{, L } = 2\text{.5 H, C } = \text{ 45 }\mu F$
• C. $R = 15\ \Omega\text{, L } = 3\text{.5 H, C } = 30\ \mu F$
• D. $R = 25\ \Omega\text{, L } = 1.\text{5 H, C } = 45\ \mu F$

Answer 1

Answer: (C)

$R = 15\ \Omega\text{, L } = 3\text{.5 H, C } = 30\ \mu F$

Answer 2

: For better tuning of an LCR circuit used for communication the circuit should possess high quality factor of resonance.

i.e., $Q = \frac{1}{R}\sqrt{\frac{L}{C}}$ should be high.

For it R should be low, L should be high and C should be low, therefore combination in option (3) is correct.