Current flow in or out?

[Meterman4U]

My understanding is that current flows along the surface of a conductor not thru or in said conductor. Can anyone help me with this. Right or wrong? Thank you

 

[kellys_eye]

Depends on the frequency.

What you're suggesting is called 'skin effect'.

 

[Meterman4U]

Having read your reply, I now remember where I got my information. It was when I was interested in short wave radio. Antennas length is calculated by the frequency because of what you stated the "skin effect". Thank you for tweeking my brain.

 

[Cannonball]

The higher the frequency the more skin effect.

 

[WHONOES]

Antenna length is calculated for of wavelength of received signal.

 

[Meterman4U]

Antenna length is calculated for of wavelength of received signal.

Thanks I have a FCC short wave amateur radio license that I have not used in years. I am beginning to remember all the radio facts. It has always been an interest of mine. Thanks for your interest.

 

[Meterman4U]

The higher the frequency the more skin effect.

and less reception capabilities, if I remember correctly. Thanks

 

[Cannonball]

I don't know about that. Skin effect is true in all conductors.

Sensitivity in antennas is affected by serval facts. The higher the frequency the shorter the antenna, but we are talking about conductors.

 

[Meterman4U]

I don't know about that. Skin effect is true in all conductors.

Sensitivity in antennas is affected by serval facts. The higher the frequency the shorter the antenna, but we are talking about conductors.

thanks for getting back to me. So.. what is the answer? Does electricity travel in or on a conductor, or both ? Thanks

 

[Meterman4U]

I don't know about that. Skin effect is true in all conductors.

Sensitivity in antennas is affected by serval facts. The higher the frequency the shorter the antenna, but we are talking about conductors.

I remember also the longer the wave-length the longer distances you could receive signals and yes... conductors are the subject. Stranded wire has more surface area and is a better conductor. Right?

 

[Cannonball]

Both. The thicker the conductor the more current it will carry for dc and ac. The higher the frequency the more surface area is needed.

The lower the rf frequency the more it will bend to follow the surface of the earth. Higher rf frequency the less it will bend. It will travel better in a straight line. I hope this helps.

 

[Meterman4U]

Ok.. why is stranded wire a better conductor. ? I am thinking that there is more surface area for the same size conductor.

 

[davenn]

Does electricity travel in or on a conductor, or both ? Thanks

depends on if it is DC or AC
For DC, it travels across the whole diameter of the conductor
For AC, it travels in a layer closer and closer to the conductor's surface as the frequency rises .... google Skin Effect

 

[Meterman4U]

depends on if it is DC or AC
For DC, it travels across the whole diameter of the conductor
For AC, it travels in a layer closer and closer to the conductor's surface as the frequency rises .... google Skin Effect

I agree. I researched on wikipedia and found the math to be WAY beyond me. The bottom line is as you stated, thanks.. I learned something

 

[duke37]

Ok.. why is stranded wire a better conductor. ? I am thinking that there is more surface area for the same size conductor.

Stranded wire will be little better than solid if the strands are not insulated from each other. Getting more surface area is usually achieved by using large diameter tube. Litz wire has many very thin strands insulated from each other and is the devil to solder. It is often used in radio frequency circuits such as ferrite rod aerials (loop sticks), IF transformers etc.

 

[Meterman4U]

Stranded wire will be little better than solid if the strands are not insulated from each other. Getting more surface area is usually achieved by using large diameter tube. Litz wire has many very thin strands insulated from each other and is the devil to solder. It is often used in radio frequency circuits such as ferrite rod aerials (loop sticks), IF transformers etc.

Thanks: I know R/F is tricky. I hope to get more involved in it. I am looking for a Arduino R/F kit project or other. Any suggestion?

 

[timff]

If I remember correctly skin effect is a major problem for higher frequency transmitters. The resistance (power loss) of a transmission line increases as the higher frequencies are not able to avail themselves of the full circular mils of the transmission conductor. I suppose the bears on the hollow tubes used in millimeter wave guides.

 

[Cannonball]

Skin effect is a fact of life. It does have it's drawbacks.

The engineers have done a very good job solving the problems caused by real high frequencies. The higher the
frequency the smaller the wave length. If the frequency is high enough the wave length will be small enough to use a wave guide.

The wave guide is more expensive but there is very little signal loss in it.

 

[Meterman4U]

If I remember correctly skin effect is a major problem for higher frequency transmitters. The resistance (power loss) of a transmission line increases as the higher frequencies are not able to avail themselves of the full circular mils of the transmission conductor. I suppose the bears on the hollow tubes used in millimeter wave guides.

I noticed a new transmission line ,just finished, strung two conductors per insulator. I wonder if that was to achieve longer cable without splicing or a more efficient transmission of electricity.

 

[Meterman4U]

Skin effect is a fact of life. It does have it's drawbacks.

The engineers have done a very good job solving the problems caused by real high frequencies. The higher the
frequency the smaller the wave length. If the frequency is high enough the wave length will be small enough to use a wave guide.

The wave guide is more expensive but there is very little signal loss in it.

I never heard of a wave guide. Some circuitry magic? I remember in short-wave radio a 40 meter signal required at least a 1/2 wave antenna to get good reception.