How to optimize parameters for making a coil with high-Q?

[Arthur C.]

I want to make a simple coil (inductor) with a Q value as high as possible.
Now, I would like to know if there are simple guidelines on how to choose
the parameters to obtain this. Parameters are:

- thickness of the wire
- number of rounds
- length of the coil
- area of cross-section

I understand that a realistic description of a coil involves (at least) a
parallel parasitic capacitance C and a series resistance R.
The resulting Q value would then be Q = (1/R) sqrt (L/C). Is this indeed the
relevant expression for Q?
If the coil is operated at a frequency of the order 1 MHz, can we assume for
R just the 'DC' series resistance of the wire, or does it change with
frequency?
And, how can C be calculated?
For inductance L I have found some useful information, but for the others
not yet...


Any suggestions? Thanks for your time,

Arthur C.

 

[Phil Allison]

"Arthur Cretin "

I want to make a simple coil (inductor) with a Q value as high as possible.

** Air cored or not ??

You are one colossal ASS for not saying so straight off.







...... Phil

 

[Arthur C.]

"Arthur Cretin "
possible.


** Air cored or not ??

You are one colossal ASS for not saying so straight off.

Thanks for the compliment. Return to sender, and take a wild guess. Or, if
you only have comments no more useful than this, I suggest you let your
frustration out somewhere else...

Arthur

 

[Bob Eld]

I want to make a simple coil (inductor) with a Q value as high as possible.
Now, I would like to know if there are simple guidelines on how to choose
the parameters to obtain this. Parameters are:

- thickness of the wire
- number of rounds
- length of the coil
- area of cross-section

I understand that a realistic description of a coil involves (at least) a
parallel parasitic capacitance C and a series resistance R.
The resulting Q value would then be Q = (1/R) sqrt (L/C). Is this indeed the
relevant expression for Q?
If the coil is operated at a frequency of the order 1 MHz, can we assume for
R just the 'DC' series resistance of the wire, or does it change with
frequency?
And, how can C be calculated?
For inductance L I have found some useful information, but for the others
not yet...


Any suggestions? Thanks for your time,

Arthur C.

To maximize Q, the wire should be a short as possible.

In general air core coils will have a higher Q than those with magnetic
materials. But the core material depends on the frequency range consistent
with the short statement. High inductance is not feasible in air core coils.

Wire should be litz wire made up of multiple strands of thin wire insulated
from each other. Especially true at 1MHz

High power, high frequency coils can be solid wire or tubing. 30MHz up.

To minimize winding capacitance, wire should be lace wound, layered back and
forth to minimize the proximity of one turn to the next. Necessary for High
Q at 1 MHz

The models of an inductor is the inductance in series with the resistance
and shunted by the stray capacitance. Below self resonance, the Q = Xl/R.
But, the R is the AC resistance of the wire at frequency, not the DC
resistance. At one MHz this value is much higher than the DC resistance
because of skin effect. That's the reason for Litz wire.

Lace winding is best done on a coil winding machine. It's probably a good
idea to go buy the inductor you need.

 

[amdx]

Can you tell us what the use of the inductor is?

Is there a maximum length and diameter your limited to?

What is the inductance your looking for?

The subtlety of inductors has kept me entertained for years and years, so
don't feel too bad, if you don't answer every question in an afternoon.

Well said John.
Mike

 

[Phil Allison]

"Arthur Cretin "

Thanks for the compliment. Return to sender, and take a wild guess.

** Go get fucked you asinine, TROLLING POS !!




.... Phil

 

[Phil Allison]

"Bob Eld"

To maximize Q, the wire should be a short as possible.

** Huh ??

In general air core coils will have a higher Q than those with magnetic
materials.

** Double huh ??

Magnetic cores increase L while leaving R and stray C the same



....... Phil

 

[Bob Eld]

"Bob Eld"


** Huh ??



** Double huh ??

Magnetic cores increase L while leaving R and stray C the same



...... Phil

True but ferrites have core losses not found in air. Of course it depends on
inductance range At one MHz it pretty much a toss up.

 

[Phil Allison]

"Bob Eld"

"Phil Allison"
True but ferrites have core losses not found in air. Of course it depends
on
inductance range At one MHz it pretty much a toss up.

** But you said " in general ....".

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.


Wot a fucking PITA jerk you are.




...... Phil

 

[Bob Eld]

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.


Wot a fucking PITA jerk you are.

...... Phil

I love you too sweet heart!

 

[Phil Allison]

"Bob Eld"

"Phil Allison"
True but ferrites have core losses not found in air. Of course it depends
on
inductance range At one MHz it pretty much a toss up.

** But you said " in general ....".

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.


Wot a fucking PITA jerk you are.




...... Phil

 

[Bob Eld]

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.


Wot a fucking PITA jerk you are.
...... Phil

Hey Phil. Want to come to California and get married? Kiss Kiss. You know I
love you!

 

[Phil Allison]

"Bob Eld = Jerk Off "

True but ferrites have core losses not found in air. Of course it depends
on inductance range At one MHz it pretty much a toss up.

** But you said " in general ....".

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.


Wot a fucking PITA jerk you are.




...... Phil

 

[Bob Eld]

"Bob Eld = Jerk Off "

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.


Wot a fucking PITA jerk you are.

...... Phil

Hi Sweetie, I just love it when you whisper sweet nothings into my ear.

 

[Phil Allison]

"Bob Eld = Fucking Jerk Off "

True but ferrites have core losses not found in air. Of course it depends
on inductance range At one MHz it pretty much a toss up.

** But you said " in general ....".

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.

Wot a fucking PITA jerk you are.

Must be a radio ham - right ?




...... Phil

 

[Bob Eld]

Fucking Jerk Off "
BULLSHIT !!!.
Wot a fucking PITA jerk you are.
pedantic ASD fucked fuckwit
Wot a wanker
**** off, idiot
FUCKING MORON
dopey pommy fuckwit has no fucking idea
Go drop dead - you pathetic, trolling MORON
FUCKING facts straight !!IDIOT !!!!!!!!!!
Dickhead.
YOU ASININE FUCKWIT MORON
LYING HIS STUPID ARSE OFF !!.
What a BULLSHITTING FUCKWIT
Wake up - you pathetic dope.
LYING HIS STUPID ARSE OFF !!.
What a PITA BULL-SHITTING FUCKWIT !!
** WHAT ABSOLUTE BOLLOCKS !!!!!

Oh Phyllis...You say the sweetest things! These are a few of my favorites.

 

[Phil Allison]

"Bob Eld = Fucking Jerk Off "

True but ferrites have core losses not found in air. Of course it depends
on inductance range At one MHz it pretty much a toss up.

** But you said " in general ....".

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.

Wot a fucking PITA jerk you are.

Must be a radio ham - right ?

Or just a total **** head.

FOAD you vile pig.



...... Phil

 

[Bob Eld]

"Bob Eld = Fucking Jerk Off "
FOAD you vile pig.
...... Phil

Oink!

 

[Phil Allison]

"Bob Eld = Fucking Jerk Off "

True but ferrites have core losses not found in air. Of course it depends
on inductance range At one MHz it pretty much a toss up.

** But you said " in general ....".

Which is complete BULLSHIT !!!.

Even at 1MHZ , for practical sizes, ferrite cored inductors are way ahead.

Wot a fucking PITA jerk you are.

Must be a radio ham - right ?

Or just a total **** head.

FOAD you vile pig.





...... Phil