What is Coaxial cable: Definition and 99 Discussions
Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric (insulating material); many coaxial cables also have a protective outer sheath or jacket. The term "coaxial" refers to the inner conductor and the outer shield sharing a geometric axis.
Coaxial cable is a type of transmission line, used to carry high-frequency electrical signals with low losses. It is used in such applications as telephone trunklines, broadband internet networking cables, high-speed computer data busses, cable television signals, and connecting radio transmitters and receivers to their antennas. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line.
Coaxial cable was used in the first (1858) and following transatlantic cable installations, but its theory wasn't described until 1880 by English physicist, engineer, and mathematician Oliver Heaviside, who patented the design in that year (British patent No. 1,407).
1. A coaxial cable is powering a light bulb with a steady flow of current (DC current). The electric potential difference between the outer and the inner conductor of the cable is delta V and the current flowing in the cable is I. The inner conductor's outer radius is a and the outer conductor's...
Homework Statement
A long coaxial cable consists of an inner solid cylinder, radius a, and an outer thin coaxial cylindrical shell, radius b. The outer shell carries a uniform surface charge density σ.
Find the uniform volume charge density ρ that the inner cylinder must have in order that...
I am trying to calculate the maximum power of a coaxial cable, based on heat transfer parameters and limiting temperatures of cable components. I've determined that a certain heat load on the conductor surface (in Watts per inch of cable) will put the dielectric above its operating temperature...
http://en.wikipedia.org/wiki/Coaxial_cable
http://en.wikipedia.org/wiki/Poynting_vector
Could a coaxial cable be used for electric current instead of radio signals?
'For example, the Poynting vector within the dielectric insulator of a coaxial cable is nearly parallel to the wire axis...
How does current flow in a coaxial cable in each of the following cases :
1. When the cable is connected to a DC voltage source.
2. When the cable is connected to an AC voltage source
3. When the outer metallic shield is connected to ground and DC and Ac sources are connected separately
I...
Hi,
I am trying to model electrical equivalent of a coaxial cable. The data I have is
1. Conductor resistance
2. Insulator resistance
3. Partial discharge
4. Insulation Thickness
5. Overall diameter
Actually I planned to use an equivalent circuit that has series connection of...
Homework Statement
An annular sheet, of thickness t=1mm and resistivity ρ=0.5Ωm, connects the inner and outer conductors of an air spaced coaxial transmission line at a point on the line. A low-frequency signal is fed into one end of the line and the other is terminated by its characteristic...
Homework Statement
I am given the following problem:
http://forum.allaboutcircuits.com/attachment.php?attachmentid=35938&d=1320027350
Homework Equations
The Attempt at a Solution
My known equations and attempt to the problem...
Homework Statement
Hi, I'm having issues with a question about a coaxial cable.
This is the question:
A coaxial cable consists of a long straight cylindrical wire of radius R1, surrounded by a coaxial cylindrical shell of radius R2. For a situation where the inner cylinder carries...
Homework Statement
I have attached the question as a pdf.
Homework Equations
I'm thinking that we take the line integral of voltage to get electric field. But I'm not sure how to proceed from here. Is the line integral from a to b? Also, how do I get the charge density having found...
One of the textbooks I've stumbled across states that the radial resistance of a coaxial cable ( current running from inner cylinder to outer cylinder via silicon in between) is given byR = [resistivity * natural log of (b/a)] / [2*pi()*(length of cable)]
where b is the outer radii and a is the...
Homework Statement
An alternating current I = I_0 \cos(\omega t) flows down a long straight wire and returns along a coaxial tube of radius a.
By constructing an appropriate Amperian loop or otherwise, and assuming that the induced electric field E goes to zero as the distance from the...
Homework Statement
A long coaxial cable consists of an inner cylindrical conductor with radius a and an outer coaxial cylinder with inner radius b and outer radius c. The outer cylinder is mounted on insulating supports and has no net charge. The inner cylinder has a uniform positive charge per...
Homework Statement
So I'm doing a problem set and the question refers to a coaxial cable, I am told that the cable consists of an inner solid cable radius (R1), which is surrounded by a outer thin tube with radius (R2) , both have the same current though them but opposite direction. I have to...
Homework Statement
Given a coaxial cable with outer conductor of radius b, and inner conductor of radius a. Prove that maximum potential is obtained when a = b /e, e is base of natural log.
Homework Equations
gauss law, ...The Attempt at a Solution
By using Gauss Law,
for a < r < b,
i have E =...
Homework Statement
A high voltage coaxial cable is used to supply power to an x-ray generator. The cable consists of an inner wire of radius r=1 mm and a thin hollow outer conductor of radius R= 10 mm. The inner wire and the outer shield have the same charge density per unit length of ...
Homework Statement
A coaxial cable consists of a long solid inner cylindrical conductor, radius a, and a thin outer cylindrical conductor of average radius b>a. Suppose the inner conductor has a line charge density of +lambda while the outer conductor has a uniformly distributed charge of...
A coaxial cable has a conductor lying at the centre of a thin walled cylindrical conductor. These conductors are separated by a plastic dielectric, and they carry equal current in opposite directions.
The radii and current are given, and I must find the magnitude and direction of magnetic...
Homework Statement
A coaxial cable has an inner core diameter 6mm and inner diameter of the outer sheath is 20mm. There are two layers of insulation between the conductors, the inner layer from a radius of 3mm to 9mm has relative permittivity of 8 while the outer layer from radius 9mm to...
Homework Statement
Say we have an infinitely long wire with radius r1 with a linear charge density +u and we have a coaxial conducting cylinder with radius r2->r3 and a linear charge density of +2u.
http://img573.imageshack.us/img573/3419/coaxialcable.png"
Now the overall aim of the...
Homework Statement
Consider an 8mm diameter coaxial cable, which consists of a central conducting wire, and an outer cylindrical conducting braid. If a charge of +30mC is placed on the inner conductor, and a charge of -30mC is placed on the outer conducting braid, what will the electric field...
1. Homework Statement
I just have a question concerning an unbalanced coaxial cable. By unbalanced, I mean that the inner and outer currents are not equal magnitudes of the opposite direction of each other. My homework problem has an inner current of +100[mA] and an outer current of 90[mA] in...
Homework Statement
I just have a question concerning an unbalanced coaxial cable. By unbalanced, I mean that the inner and outer currents are not equal magnitudes of the opposite direction of each other. My homework problem has an inner current of +100[mA] and an outer current of 90[mA] in the...
Homework Statement
A copper wire is surrounded by insulation, then a copper mesh, and then an outside insulation.
Assume the current in the inner conductor is going into the page and an equal magnitude of current is flowing out of the page in the copper mesh outer conductor.
a. Which...
Homework Statement
If I have two co axial conductors at V = 0 and the dielectric has a free charge density. Is that physically possible?
Homework Equations
No relevant equations
The Attempt at a Solution
I am not sure if you can have free charge density in a dielelctric when both conductors...
Homework Statement
Type P241B coaxial cable has an inductance of 0.4 μH/m and a capacitance of 40 pF/m.
The diagram below shows a 100 m length of this cable connected to a battery and switch at the sending end and a 50Ω resistor at the receiving end.
(a) If S is closed, what initial current...
Homework Statement
Consider a coaxial cable that consists of inner/outer conductors of radii a and b, and it is filled with electron cloud with volumetric charge density of ρv = Υ/ρ [C/m3] for a < ρ < b. If outer conductor is +Vo [V] more positive than inner conductor, find E field between...
Homework Statement
A coaxial cable of circular cross section has a compound dielectric. The inner conductor has an outside radius a , which is surrounded by a dielectric sheath of dielectric constant K_1 and of outer radius b . Next comes another dielectric sheath of dielectric constant...
Homework Statement
If the outer conductor of a coaxial cable has radius 3.5 , what should be the radius of the inner conductor so that the inductance per unit length does not exceed 55 per meter?
Homework Equations
The Attempt at a Solution
1.385
I'm attempting to teach myself some electrostatics, so that I'll be prepared when I head back to school full time.
Homework Statement
Determine the electric field inside the inner conductor, between the conductors, and outside the conductors of a coaxial cable when the inner conductor is...
http://img154.imageshack.us/img154/165/integrallll.jpg
After working it out myself, I have the logarithim part equal to:
[ln b - lna] + [ln c - ln b] = [ln b/a + ln c/b] = ln c/a (Not sure about this statement!)
I don't understand where the c^2 and ab came from with this integral...
Homework Statement
A coaxial cable consists of two long, concentric, perfect conductors. The inner conductor is a right circular cylinder of radius a, while the outer conductor is a thin, hollow annular cylinder of inner radius b.
Suppose a half-infinite length of such a coaxial cable...
Consider a coaxial cable with inner radius a and outer radius b. The potential difference between the inner and outer conducter is V. How can it be shown that the electric field at a distance r from the inner conducter is given by:
E = \frac{V}{r ln\frac{b}{a}}
Any help would be much...
Homework Statement
Hi all.
I have the following expression, which relates the incoming amplitude with the reflected amplitude at a point x = L in a coaxial cable:
A_{\text{reflected}} = \frac{R-Z_0}{R+Z_0}A_{\text{incoming}}.
Here R is the resistance at the point x = L and Z0 is the...
Homework Statement
Compare sound waves to waves in coaxial cables a.k.a. T.E.M.
I really have no idea how to answer this question. I've been researching and researching, and so far i can't find any information about WAVES for coaxial cables. Any help?
Thanks.
Homework Equations...
Homework Statement
http://smg.photobucket.com/albums/v68/jumpboyb/?action=view¤t=scan0001.jpg"
Pretty much looking for a general equation for capacitance of a coaxial cable per meter length.
given:
-a diagram (click link)
-two radii
-dielectric material
-outer conductor is...
Homework Statement
A coaxial cable consists of two very long cylindrical tubes, separated by linear insulating material of magnetic susceptibility χm (see Figure). A current I flows down the inner conductor and returns along the outer one, in each case the current distributes itself...
Homework Statement
Immediately outside a very long cylindrical wire of radius r1 = 1mm, the electric field is 40kV/m directed towards the wire's surface.
A hollow cylindrical metal tube with inner radius r2 = 3mm is now placed around the wire, to form a coaxial cable. What will be the charge...
Homework Statement
a coaxial cable carries current as follows: (see attachment)
at point P, 0.3 meters from the central axis, the magnetic field is 0.005 Teslas, what is current, I?
Homework Equations
magnetic field solenoid, B = mu_0(n)I where mu_) is constant = 4pi*10^-7, n is...
Homework Statement
If anyone could clarify this statement for me, I'm having a bit of difficulty interpreting what the heck I'm supposed to do:
"For a given potential difference V0 between the inner and outer conductors and for a given fixed value of b, determine the inner radius a for which...
Hi,
I am doing an experiment with a coaxial cable and i want to Count out it expected RC-constant for the cable.
I have measured the resistance for the cable, but when i count the RC, the resistansen that will be used only is the half of it resistans measured in the beginning.
Why...
Hi,
As you know the capacitance per unit length of a standard coaxial cable is
C_{coax} = \frac{2 \pi \varepsilon_{0} \varepsilon_{r}}{\ln{\frac{b}{a}}}
where b is the radius of the cable and a is radius of the central conductor.
.
If we only want to know the capacitance of a...
Homework Statement
"A coaxial cable consists of an inner wire and a concentric cylindrical outer conductor. If the conductors carry equal but opposite charges, show that there is no net charge on the outside of the outer conductor.
Homework Equations
Gauss's Law
The Attempt at a...
Homework Statement
GIVEN:
a=radius of inner electrode = 0.05 cm
b=radius of outer electrode = 0.5 cm
Vo = 130 V
QUESTION: What is the electric field at surface of the inner electrode in units of V/m?
Homework Equations
Given equations
Potential at radius r b/w inner&outer electrodes...
hiya guys,
I'm having a large amount of trouble with a problem that I've been working through (currently revising for an uncoming exam in electromagnetism, along with a lot of other things). the problem is stated as follows (condensed):
coaxial cable - inner cylinder radius a, out cylinder...
Why is the coaxial cable impedance independent of it's length? I am considering the model shown in the attached picture. Since the resistance, capacitance and inductance are all dependent of the length of the cable in one way or another how come the impedance is not? I also can't find any...
Homework Statement
I have to find the magnetic vector potential in a round coaxial cable. The internal conductor has a finite (known) conductivity. The external conductor is a perfect electrical conductor. Both the radius of the internal and the external conductors are known.
I have to assume...
The figure below is a cross-sectional view of a coaxial cable. The center conductor is surrounded by a rubber layer, which is surrounded by an outer conductor, which is surrounded by another rubber layer. In a particular application, the current in the inner conductor is 1.86 A out of the page...
Hello all,
I once wanted to plug two coaxial cables together (tv - antenna),
and when I touched the coaxial cable coming from the antenna,
I got an electric shock (a weak one, like if you get an electric shock if
you are charged and touch metal).
My questions:
1) Why did I get an...