Calculating Distributed Capacitance of a Bifilar Coil?

In summary, the conversation discusses the calculation of distributed capacitance in a multi-layer bifilar coil. The group is looking for ways to minimize leakage inductance and discusses using Litz wire and bifilar windings. They also provide equations and resources for calculating the capacitance.
  • #1
HMS-776
63
0
Hello everyone,

I have been tirelessly searching the net trying to find out how to calculate the distributed capacitance of a multi-layer bifilar coil.

Just wondering if anyone here can point me in the right direction?
 
Engineering news on Phys.org
  • #2
For Hi-Q high frequency coils, you want Litz wire. The turn-to-turn capacitance is the same as single conductor wire, but the eddy current (skin depth) losses are less. Litz wire is multiconductor wire with insulated strands. What do you mean by bifilar coil? See

http://www.die.ing.unibo.it/pers/grandi/papers/ia99.pdf

Bob S
 
  • #3
Bob S said:
What do you mean by bifilar coil?

Bifilar windings are when the primary and secondary wires are wound together on the bobbin or core. It's generally done to minimize leakage inductance Lk, at the expense of much higher winding-to-winding capacitance Cww.

http://en.wikipedia.org/wiki/Bifilar_winding

I'm not sure of a good way to calculate the capacitance, though...
 
  • #4
berkeman said:
Bifilar windings are when the primary and secondary wires are wound together on the bobbin or core. It's generally done to minimize leakage inductance Lk, at the expense of much higher winding-to-winding capacitance Cww.

http://en.wikipedia.org/wiki/Bifilar_winding

I'm not sure of a good way to calculate the capacitance, though...
The capacitance between the two conductors in a bifilar winding (neglecting turn-to-turn effects in a coil) is the same whether the bifilar pair is wound in a coil or in a long straight line. The capacitance per unit length is

C = πε0/[cosh-1(D/2R)]

where D is the center-to-center spacing of the two round conductors, each of radius R. (See Smythe Static and Dynamic Electricity Third Edition, Section 4.14).

It is also possible to get to this number by calculating the transmission line impedance of a twisted pair or a twin-line transmission line, and knowing that

a) The signal velocity in an air-filled transmission line is c = 1/sqrt(LC), and

b) The transmission line characteristic impedance is Z = sqrt(L/C)

where L and C are the inductance and capacitance per unit length.

Also look up Lecher Line capacitance in http://en.wikipedia.org/wiki/Lecher_lines

Bob S
 
  • #5
Thanks Bob S, I greatly appreciate it. although I am really hoping to find the equation one would use for a multi layer coil.
 

1. How is distributed capacitance of a bifilar coil calculated?

The distributed capacitance of a bifilar coil can be calculated by using the following formula: C = (k * A * ε) / d, where C is the distributed capacitance, k is the dielectric constant, A is the area of the coil, ε is the permittivity of free space, and d is the distance between the two wires of the coil.

2. What is the purpose of calculating the distributed capacitance of a bifilar coil?

Calculating the distributed capacitance of a bifilar coil is important in understanding the electrical properties of the coil. It helps in determining the resonant frequency, impedance, and other parameters that affect the performance of the coil in various applications.

3. How does the distributed capacitance of a bifilar coil affect its performance?

The distributed capacitance of a bifilar coil affects its performance by influencing its impedance, resonance frequency, and bandwidth. It also affects the efficiency of the coil in transferring energy and the overall electrical properties of the coil.

4. What factors can affect the distributed capacitance of a bifilar coil?

The distributed capacitance of a bifilar coil can be affected by various factors such as the distance between the wires, the dielectric constant of the material between the wires, the length and diameter of the wires, and the frequency of the current passing through the coil.

5. Are there any practical applications of calculating the distributed capacitance of a bifilar coil?

Yes, there are practical applications of calculating the distributed capacitance of a bifilar coil. It is commonly used in designing and analyzing high-frequency and radio frequency circuits and devices such as antennas, transformers, and inductors. It is also useful in the design of wireless power transfer systems and other electromagnetic devices.

Similar threads

  • Electrical Engineering
Replies
11
Views
2K
  • Electrical Engineering
2
Replies
47
Views
6K
  • Electrical Engineering
Replies
7
Views
2K
  • Electrical Engineering
Replies
11
Views
2K
Replies
10
Views
325
Replies
16
Views
10K
Replies
7
Views
3K
  • Electrical Engineering
Replies
4
Views
5K
  • Electrical Engineering
Replies
1
Views
349
  • Electrical Engineering
Replies
4
Views
2K
Back
Top