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A television channel is assigned the frequency range from 54 MHz to 60 MHz. A series RLC tuning circuit in a TV receiver resonates in the middle of this frequency range. The circuit uses a 14 pF capacitor.

In order to function properly, the current throughout the frequency range must be at least 50% of the current at the resonance frequency. What is the minimum possible value of the circuit's resistance?

User Surfer
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The minimum possible value of the circuit's resistance is approximately 2100 Ω (to two significant figures).

Here's how to find the minimum possible resistance:

Calculate the bandwidth:

The current must be at least 50% of the resonance current within the frequency range of 54-60 MHz. This means the bandwidth is 6 MHz (60 MHz - 54 MHz).

Determine the quality factor (Q):

The Q factor determines the sharpness of the resonance peak. A lower Q means a wider bandwidth.

Use the formula Q = f_res / bandwidth:

Q = 57 MHz / 6 MHz ≈ 9.5

Calculate the minimum resistance:

The Q factor is also related to the resistance by Q = R / (2 * pi * f_res * L).

Rearrange for R:

R = Q * 2 * pi * f_res * L

Plug in values, using the inductance L = 0.56 μH (from your answer to part A):

R = 9.5 * 2 * pi * 57 * 10^6 * 0.56 * 10^-6 ≈ 2050 Ω

Therefore, the minimum possible value of the circuit's resistance is approximately 2100 Ω (to two significant figures).

The probable question can be: Question: A television channel is assigned the frequency range from 54 MHz to 60 MHz. A series RLC tuning circuit in a TV receiver resonates in the middle of this frequency range. The circuit uses a 14 pF capacitor. A) What is the value of the inductor? I found the answer of this to be L = .56 uH I need help with question B) B) In order to function properly, the

A television channel is assigned the frequency range from 54 MHz to 60 MHz. A series RLC tuning circuit in a TV receiver resonates in the middle of this frequency range. The circuit uses a 14 pF capacitor.

A) What is the value of the inductor?

I found the answer of this to be L = .56 uH

I need help with question B)

B) In order to function properly, the current throughout the frequency range must be at least 50% of the current at the resonance frequency. What is the minimum possible value of the circuit's resistance?

Express your answer to two significant figures and include the appropriate units.

User Simple Sandman
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7.9k points