Question

Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?

Options

• R = 20 Ω, L = 1.5 H, C = 35 μF

• R = 25 Ω, L = 2.5 H, C = 45 μF

• R = 15 Ω, L = 3.5 H, C = 30 μF

• R = 25 Ω, L = 1.5 H, C = 45 μF

Answer 1

R = 15 Ω, L = 3.5 H, C = 30 μF

Explanation:

Quality factor (Q) of an L-C-R circuit is given by,

Q = \[\frac{1}{R}\sqrt{\frac{L}{C}}\]

Tuning of an L-C-R circuit depends on quality factor of the circuit. Tuning will be better when quality factor of the circuit is high.

For Q to be high. R should be low, L should be high and C should be low. Therefore, option (c) is most suitable.