I need to make a tank circuit consisting of a loop and a capacitor knowing that it needs to have a resonant frequency of about 41 kHz

I want to calculate the dimensions of the loop required and i noticed that often these loops are made from copper, why is that the case? i looked up its relative permeability and i found it to be almost equal to one and there are other metals with much better permeability.

 

Resistivity = conductivity.
Max.

 

Because silver is usually too expensive or otherwise impractical for the application.

 

I need to make a tank circuit consisting of a loop and a capacitor knowing that it needs to have a resonant frequency of about 41 kHz

I want to calculate the dimensions of the loop required and i noticed that often these loops are made from copper, why is that the case? i looked up its relative permeability and i found it to be almost equal to one and there are other metals with much better permeability.

Magnetic permeability is not the issue, because the field is primarily not in the metal of the coil itself. Copper is used because of its high conductivity (= low resistivity), its ductility, thermal characteristics, etc. all at a practical cost.

 

What dimensions have you come up with so far?
What kind of capacitor are you considering?
What is the acceptable tolerance on the value of 41 kHz.?
BTW - what is the application for such a tank circuit?

Back of the envelope calculations reveal that the values you need may be physically unrealizeable.
Have you considered the sensitivity of the resonant frequency to component values?

 

https://www.allaboutcircuits.com/tools/tank-circuit-resonance-calculator/

https://www.allaboutcircuits.com/tools/wire-loop-inductance-calculator/

... haven't checked ... these calculators might work.

... edited

 

https://www.allaboutcircuits.com/tools/tank-circuit-resonance-calculator/

https://www.allaboutcircuits.com/tools/wire-loop-inductance-calculator/

... haven't checked ... these calculators might work.

... edited

They work if you have some idea of the answer ahead of time.

 

I need to make a tank circuit consisting of a loop and a capacitor knowing that it needs to have a resonant frequency of about 41 kHz

I want to calculate the dimensions of the loop required and i noticed that often these loops are made from copper, why is that the case? i looked up its relative permeability and i found it to be almost equal to one and there are other metals with much better permeability.

Cost effective mostly. Higher up the SW band, you sometimes find silver coated copper inductors for lower resistance right where the skin effect manifests itself. High end UHF and higher - you might find the occasional solid silver inductor.

At 40kHz - Litz wire is probably worth a look.

 

Hello,

Have a look at the attached PDF for a 10 to 150 kHz antenna.

Bertus

 

... as far as numbers going into the calculators, one possible combination of values is:

12.5 uF capacitor
12 μH inductor

... Where the 12 μH inductor is a 3 inch diameter tube with a circular loop diameter of 15 feet.

For the sake of discussion, the inductor is constructed from 3 in. dia. muffler tube, using a custom tube bending machine.

... The resulting numerically computed resonant frequency of the parallel circuit is:

41.1 kHz

... actual construction and a frequency check has yet to be considered.

 

Hello,

Have a look at the attached PDF for a 10 to 150 kHz antenna.

Bertus

The TS has not stated that he intends to use the tank circuit for a receiver.

 

... as far as numbers going into the calculators, the critical resonant values are:

12.5 uF capacitor
0.000012 H inductor

... Where the 12 μH inductor is a 3 inch diameter tube with a circular loop diameter of 15 feet.

For the sake of discussion, the inductor is constructed from 3 in. dia. muffler tube, using a custom tube bending machine.

... The resulting numerically computed resonant frequency of the parallel circuit is:

41.1 kHz

... actual construction and a frequency check has yet to be considered.

Those are not the only workable values. In fact there are an infinite number of solutions to the basic problem.

 

41 kHZ seems like it could be an induction heating frequency, or an ultrasonic welding application. There are also anti-personell applications that I won't discuss. With the TS not stating any application or claiming any knowledge or understanding, we need a lot more explanation as to the purpose.

 

All he asked is why people use copper. Asked and answered.

 

As often happens, this thread has wandered. A 15 foot diameter single turn with a 12.5mFd capacitor would not be practical for any application that I can imagine, and making it out of steel would reduce the Q quite a bit. So I am still wondering what the TS wants to accomplish with the tuned circuit, because that makes a great deal of difference in a number of variables.

AND, to answer the question as to why copper: Copper is the most cost effective material for almost all electrical connections and circuits, since it provides quite good conductivity with adequate workability and enough strength, while being easy to connect and somewhat corrosion resistant.
That being the case, next comes aluminum, which is also used a lot where cost and weight are larger considerations. Today most high voltage power lines are made of an aluminum alloy because for the long distance transmission lines it is more cost effective. Although it is much more challenging to connect in a satisfactory manner, the cost and weight savings make it the better choice.

 

What dimensions have you come up with so far?
What kind of capacitor are you considering?
What is the acceptable tolerance on the value of 41 kHz.?
BTW - what is the application for such a tank circuit?

Back of the envelope calculations reveal that the values you need may be physically unrealizable.
Have you considered the sensitivity of the resonant frequency to component values?

Hello

The reason i want to make this loop is that i want to make a passif resonator that i will use to increase the distance between the transmitter and receiver of a WPT model based on inductive coupling with resonance.

41 kHz is imposed on me by the coils i have available to
use as transmitter and receiver.
I eventually did some calculations and came up with these realizable values: C = 51 uF and L = 2.94e-7 H
the dimensions of the loop: diameter of wire = 1 mm diameter of loop = 10 cm (picture: )

i am using five 10 uF capacitors in parallel.


Here are the characteristics of the transmitter and receiver:
L = 0.15 H (imposed)
C = 100 pF (chosen to be able to have realizable passive resonators with the same resonant frequency, here: 41 093,62 Hz)

What do you mean by sensitivity of the resonant frequency to component values?

I apologize for the delayed answer.

 

What dimensions have you come up with so far?
What kind of capacitor are you considering?
What is the acceptable tolerance on the value of 41 kHz.?
BTW - what is the application for such a tank circuit?

Back of the envelope calculations reveal that the values you need may be physically unrealizable.
Have you considered the sensitivity of the resonant frequency to component values?

Hello

The reason i want to make this loop is that i want to make a passive resonator that i will use to increase the distance between the transmitter and receiver of a WPT model based on inductive coupling with resonance.

41 kHz is imposed on me by the coils i have available to
use as transmitter and receiver.
I eventually did some calculations and came up with these realizable values: C = 51 uF and L = 2.94e-7 H
the dimensions of the loop: diameter of wire = 1 mm diameter of loop = 10 cm
i am using five 10 uF capacitors in parallel.


Here are the characteristics of the transmitter and receiver:
L = 0.15 H (imposed)
C = 100 pF (chosen to be able to have realizable passive resonators with the same resonant frequency, here: 41 093,62 Hz)

What do you mean by sensitivity of the resonant frequency to component values?

PS: I apologize for the delayed answer.

 

Hello

The reason i want to make this loop is that i want to make a passive resonator that i will use to increase the distance between the transmitter and receiver of a WPT model based on inductive coupling with resonance.

41 kHz is imposed on me by the coils i have available to
use as transmitter and receiver.
I eventually did some calculations and came up with these realizable values: C = 51 uF and L = 2.94e-7 H
the dimensions of the loop: diameter of wire = 1 mm diameter of loop = 10 cm
i am using five 10 uF capacitors in parallel.


Here are the characteristics of the transmitter and receiver:
L = 0.15 H (imposed)
C = 100 pF (chosen to be able to have realizable passive resonators with the same resonant frequency, here: 41 093,62 Hz)

What do you mean by sensitivity of the resonant frequency to component values?

PS: I apologize for the delayed answer.

A resonant loop such as the one you describe will have a fairly high "Q" factor, which means that it will be very selective and tend to reject signals that are not exactly at the resonant frequency. That is useful for avoiding interference but it also means that it must be tuned precisely to the correct frequency.for adequate performance. so if the value of the capacitors that you use are not exactly as marked then the resonant frequency may not be exactly as you calculated. So you may need to do some adjustments. THAT is the explanation of the sensitivity of the resonant frequency to component values.

 

A resonant loop such as the one you describe will have a fairly high "Q" factor, which means that it will be very selective and tend to reject signals that are not exactly at the resonant frequency. That is useful for avoiding interference but it also means that it must be tuned precisely to the correct frequency.for adequate performance. so if the value of the capacitors that you use are not exactly as marked then the resonant frequency may not be exactly as you calculated. So you may need to do some adjustments. THAT is the explanation of the sensitivity of the resonant frequency to component values.

Yes, this. This is why every practical case for such loops include variable capacitors or a way to change the effective loop size to tune them. It is not going to be possible to use fixed components without some sort of trim ability to account for inevitable physical variations.

Look at designs for loop antennas for practical tuning circuits.

 

The problem is that the variable capacitors i have only have discrete values: