- #1

davenn

Science Advisor

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2019 Award

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## Main Question or Discussion Point

This query comes from not being able to answer some one else's query

it show's I have been away from textbooks and classrooms way too long ( see my signature )

I have forgotten my basics

These RL circuits

Now I realise

and following that

For

1) antenna

2) some other circuit on a separate module ( possibly/probably capacitively coupled)

or if circuit

Bouncing around a number of www sites infers that the parallel RL is used as a form impedance matching

between the source and load ?

I cannot find specific comments for another use ... is there one ?

I was considering a filter ....

with ref to ....

http://amrita.vlab.co.in/?sub=1&brch=75&sim=322&cnt=1

With an ac signal applied to it, the parallel RL circuit shown below offers significant impedance to the flow of current. This impedance will
change with frequency, since that helps determine XL, but for any given frequency, it will not change over time.

Then gets into a mass of complex impedance calc's as most sites do

one place seen was in an FM phase modulator circuit ....

I haven't played with phase modulation circuits ... so not too sure of the process there

a little help in understanding please

cheers

Dave

it show's I have been away from textbooks and classrooms way too long ( see my signature )

I have forgotten my basics

These RL circuits

Now I realise

**A**and**B**are just the same with the RL rotatedand following that

**C**would be the same as**B**with the load inserted below the RLFor

**C**... What difference is there if the load is say1) antenna

2) some other circuit on a separate module ( possibly/probably capacitively coupled)

or if circuit

**B**and the load was parallel across the source and the RL network ?Bouncing around a number of www sites infers that the parallel RL is used as a form impedance matching

between the source and load ?

I cannot find specific comments for another use ... is there one ?

I was considering a filter ....

with ref to ....

http://amrita.vlab.co.in/?sub=1&brch=75&sim=322&cnt=1

**Theory:**With an ac signal applied to it, the parallel RL circuit shown below offers significant impedance to the flow of current. This impedance will

Then gets into a mass of complex impedance calc's as most sites do

one place seen was in an FM phase modulator circuit ....

I haven't played with phase modulation circuits ... so not too sure of the process there

a little help in understanding please

cheers

Dave