An RF voltmeter with a detector probe is used to measure the voltage across a 75-Ω resistive load. The frequency is 137.5 MHz. The measured voltage is 8 V. What power is dissipated in the load?

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Accepted Answer

An RF power meter with a detector probe produces a peak reading of voltage [latex]V_P[/latex]:

[latex]V_P[/latex] = 8 V
[latex]V_{rms}[/latex] = 0.707[latex]V_P[/latex]
= 0.707(8) = 5.656 V
Power = [latex]\frac{V^2}{ R}[/latex] = [latex]\frac{(5.656)^2}{ 75}[/latex]
=[latex]\frac{ 32} {75}[/latex] = 0.4265 W
= 426.5 mW

Question 22.1: An RF voltmeter with a detector probe is used to measure the...

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