questions in RF Circuit Design book

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baby_1

Hello dear

in the first page "The effect of component q on loaded q"
this paragraph shows me that the equivalent of the inductor with series resistor in parallel.
1-what the inductor in parallel shows us?(at resonant and after and befor)

in the next page(2)
how does it draw the equivalent of inductor resistor in scheme 2-16C from 2-16B?because we have only inductor q and capacity in Henry with out resonant frequency?

Thanks

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FvM

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1- The equivalent circuit is only valid for a single frequency
2- The resonance frequency is implicitely given by the parallel capacitor

baby_1

baby_1

Points: 2

baby_1

Thanks FVm such as always
1-the equvalent shows what?could tell me an example?
2-could you calculate the Resistor in question 2 because according the text its related to inductor not capacitor?:

FvM

Super Moderator
Staff member
A RL series circuit with the impedance Z = R + jωL can be replaced by a parallel circuit with identical impedance
1/Z = Y = 1/R1 + 1/jωL1.

because according the text its related to inductor not capacitor
I didn't tell different. The capacitor allows to calculate the resonance frequency.

baby_1

baby_1

Points: 2

baby_1

Hello fvm
1-could you calculate with numeric equation according the uploaded file?i want to know how it find the 4.5Kohm resistor?
2-parallel equvalent of inductor with resistor shows us that in the resonant frequency we can omit the inductor and assume the parallel resistor only or shows us something else?

FvM

Super Moderator
Staff member
1-could you calculate with numeric equation according the uploaded file?i want to know how it find the 4.5Kohm resistor?
Unfortunately I can't because the numbers are apparently wrong. Rs=4.5k and Q=10 refers to XL=450 ohm. For the given L and C, XL in resonance is 45 ohm however. The numbers fit e.g. for L=5µ.

2- Yes. Omit L and C in resonance.

baby_1

baby_1

Points: 2
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