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Home > Archive > Electrical Engineering > March 2008 > WHETHER THE RESISTANCE IN AC AND DC, ARE SAME R DIFFERENT....
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WHETHER THE RESISTANCE IN AC AND DC, ARE SAME R DIFFERENT....
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| VIDHYA 2008-03-23, 9:25 am |
| I NEED 2 KNOW WHETHER THE RESISTANCE IN AC AND DC, ARE SAME R
DIFFERENT....IN AC V R DEALIN WID PHASE ANGLE N SAYIN TAT BOTH WERE IN
PHASE(CURRENT N VOLTAGE)....COULD ANYONE SUGGEST THE REASON BEHIND
THIS? IN DC V R SAYIN TAT BOTH WERE HAVIN LINEAR RELATIONSHIP ! SO
JUSTIFY ME WHETHER THE RESISTANCE IN AC AND DC, ARE SAME OR NOT?
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| John Nice 2008-03-23, 9:25 am |
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"VIDHYA" <vidhya36@gmail.com> wrote in message
news:725d4d3c-45d8-40c4-8e8a-fa0b4c281426@c19g2000prf.googlegroups.com...
>I NEED 2 KNOW WHETHER THE RESISTANCE IN AC AND DC, ARE SAME R
> DIFFERENT....IN AC V R DEALIN WID PHASE ANGLE N SAYIN TAT BOTH WERE IN
> PHASE(CURRENT N VOLTAGE)....COULD ANYONE SUGGEST THE REASON BEHIND
> THIS? IN DC V R SAYIN TAT BOTH WERE HAVIN LINEAR RELATIONSHIP ! SO
> JUSTIFY ME WHETHER THE RESISTANCE IN AC AND DC, ARE SAME OR NOT?
>
>
Could you repeat it in English, please, and don't S H O U T
John
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| Muththu 2008-03-23, 1:25 pm |
| On Mar 23, 11:02=A0pm, VIDHYA <vidhy...@gmail.com> wrote:
> I NEED 2 KNOW WHETHER THE RESISTANCE IN AC AND DC, ARE SAME R
> DIFFERENT....IN AC V R DEALIN WID PHASE ANGLE N SAYIN TAT BOTH WERE IN
> PHASE(CURRENT N VOLTAGE)....COULD ANYONE SUGGEST THE REASON BEHIND
> THIS? IN DC V R SAYIN TAT BOTH WERE HAVIN LINEAR RELATIONSHIP ! SO
> JUSTIFY ME WHETHER THE RESISTANCE IN AC AND DC, ARE SAME OR NOT?
Two reasons:
1. Skins effect for individual conductors. See http://en.wikipedia.org/wiki/=
Skin_effect
2. Proximity effect for bundled conductors. See
http://en.wikipedia.org/wiki/Proximity_effect_(electromagnetism)
In both cases the resistance increases with frequency due a reduction
in effective cross-sectional area for conduction.
If you meant the resistive component of an arbitrary impedance, then
this is the same for DC or AC. But I suspect you might be struggling
with the distinction between pure (ohmic) resistance and reactances.
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| gala.mayur@yahoo.com 2008-03-24, 9:25 am |
| On Mar 23, 3:02=A0pm, VIDHYA <vidhy...@gmail.com> wrote:
> I NEED 2 KNOW WHETHER THE RESISTANCE IN AC AND DC, ARE SAME R
> DIFFERENT....IN AC V R DEALIN WID PHASE ANGLE N SAYIN TAT BOTH WERE IN
> PHASE(CURRENT N VOLTAGE)....COULD ANYONE SUGGEST THE REASON BEHIND
> THIS? IN DC V R SAYIN TAT BOTH WERE HAVIN LINEAR RELATIONSHIP ! SO
> JUSTIFY ME WHETHER THE RESISTANCE IN AC AND DC, ARE SAME OR NOT?
AC HAS UTERNATING CURRENT AS WEL AS DC HAS DIRECT CREENT.THEY R NOT
SAME
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| Palindrome 2008-03-24, 9:25 am |
| gala.mayur@yahoo.com wrote:
> On Mar 23, 3:02 pm, VIDHYA <vidhy...@gmail.com> wrote:
>
> AC HAS UTERNATING CURRENT AS WEL AS DC HAS DIRECT CREENT.THEY R NOT
> SAME
One way of looking at it is that dc is simply very, very slowly changing
ac. Unless you are going to explain the difference between dc and ac
with a frequency of
0.000000000000000000000000000000000000000000000000000000000000000001 Hz?
--
Sue
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| daestrom 2008-03-24, 5:25 pm |
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"Palindrome" <me9@privacy.net> wrote in message
news:RfNFj.710629$X56.662336@fe06.news.easynews.com...
> gala.mayur@yahoo.com wrote:
>
> One way of looking at it is that dc is simply very, very slowly changing
> ac. Unless you are going to explain the difference between dc and ac with
> a frequency of
> 0.000000000000000000000000000000000000000000000000000000000000000001 Hz?
>
As when studying Fourier. Any repeating waveform can be reduced to the sum
of an infinite number of sin and cosine waves.
And with a sufficiently warped mind, *anything* can be considered a
repeating waveform, including the Big-Bang.... :-)
daestrom
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| Don Kelly 2008-03-25, 8:25 pm |
| ----------------------------
"VIDHYA" <vidhya36@gmail.com> wrote in message
news:725d4d3c-45d8-40c4-8e8a-fa0b4c281426@c19g2000prf.googlegroups.com...
>I NEED 2 KNOW WHETHER THE RESISTANCE IN AC AND DC, ARE SAME R
> DIFFERENT....IN AC V R DEALIN WID PHASE ANGLE N SAYIN TAT BOTH WERE IN
> PHASE(CURRENT N VOLTAGE)....COULD ANYONE SUGGEST THE REASON BEHIND
> THIS? IN DC V R SAYIN TAT BOTH WERE HAVIN LINEAR RELATIONSHIP ! SO
> JUSTIFY ME WHETHER THE RESISTANCE IN AC AND DC, ARE SAME OR NOT?
It appears that you are confused between resistance and impedance. The
Impedance for DC is the resistance but for AC it includes the effect of
inductance or capacitance (hence the phase angle) If, in AC the phase angle
is 0- that implies resistance only and this will be somewhat higher than the
DC resistance depending on frequency.
The voltage current relationship is treated as linear in both cases.
--
Don Kelly dhky@shawcross.ca
remove the X to answer
P.S. Please don't write in capitals- use a normal mix of upper and lower
case letters.
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| VIDHYA 2008-03-26, 9:25 am |
| ok frnd we know that Rdc=1.6*Rac....if this is true means , resistor's
resistance value while considering na why we are taking the value of
resistance multiplied wid 1.6....it remains the same in dc and ac
na.....there no change will com or what?
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| Don Kelly 2008-03-27, 3:25 am |
| ----------------------------
"VIDHYA" <vidhya36@gmail.com> wrote in message
news:0d445ad0-ac84-473f-9cf0-99516bc2f912@u10g2000prn.googlegroups.com...
> ok frnd we know that Rdc=1.6*Rac....if this is true means , resistor's
> resistance value while considering na why we are taking the value of
> resistance multiplied wid 1.6....it remains the same in dc and ac
> na.....there no change will com or what?
Do you not mean Rac =1.6Rac which is possible due to skin effect as
mentioned by someone else?.
For AC the current tends to flow in the outer part of the conductor while it
is uniformly distributed through the conductor for DC. This means that the
effective area of the conductor is smaller for AC than it is for DC so that
the AC resistance is higher than the DC resistance and the difference is
frequency and conductor size dependent.
It might be a good idea to rephrase your question so that at least some of
the rules of English apply. frnd, wid, com can be guessed at but na is a
mystery so try to avoid word short cuts.
--
Don Kelly dhky@shawcross.ca
remove the X to answer
>
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| VIDHYA 2008-03-27, 9:25 am |
| On Mar 27, 8:52=A0am, "Don Kelly" <d...@shaw.ca> wrote:
> ----------------------------"VIDHYA" <vidhy...@gmail.com> wrote in message=
>
> news:0d445ad0-ac84-473f-9cf0-99516bc2f912@u10g2000prn.googlegroups.com...
>
[color=darkred]
>
> Do you not mean Rac =3D1.6Rac which is possible due to skin effect as
> mentioned by someone else?.
> For AC the current tends to flow in the outer part of the conductor while =
it
> is uniformly distributed through the conductor for DC. This means that the=
> effective area of the conductor is smaller for AC than it is for DC so tha=
t
> the AC resistance is higher than the DC resistance and the difference is
> frequency and conductor size dependent.
>
> It might be a good idea to rephrase your question so that at least some of=
> the rules of English apply. =A0frnd, wid, com can be guessed at but =A0na =
is a
> mystery so try to avoid word short cuts.
> --
>
> Don Kelly d...@shawcross.ca
> remove the X to answer
>
>
>
> - Hide quoted text -
>
> - Show quoted text -
ok friend....thanks for your kind specification ,surely i will rectify
it friend...
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