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Resistance is inversely-proportional to the cross-sectional area of a conductor. When a d.c. current flows, the charge carriers distribute themselves across the whole of the conductor's cross-section. When a.c. current flows, due to something called the 'skin effect', the charge carriers tend to flow towards the surface of the conductor -thus reducing the effective cross-sectional area of the conductor. So, the resistance to a.c. is higher than the resistance to d.c. At mains' frequencies (50/60 Hz), the 'skin effect' is relatively low, but the effect increases significantly with an increase in frequency. So the difference between 'd.c. resistance' and 'a.c. resistance' increases as the frequency increases.

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What is the formula to calculate AC resistance if the DC resistance is known?

AC resistance is the term used to describe the elevated value of resistance due to the reduction in a conductor's effective cross-sectional area due to the the skin effect caused by an alternating current. The skin effect describes how AC current tends to flow towards the surface of a conductor, rather than being distributed across the entire cross-sectional area as is the case for a DC current.For 50/60 Hz supplies the skin effect is not great and, so, there will not be a great difference between the DC resistance and AC resistance of a winding. Accordingly, it will be very difficult to calculate the winding's AC resistance, as its value is likely to be masked by experimental error and the accuracy of the instruments.In theory, by using a wattmeter and an ammeter, the resistance of a load -in this case a winding- the readings can be inserted into the equation: R = P/I2. Using a DC supply will reveal the (DC) resistance value, and using an AC supply will reveal the AC resistance value. As explained, a combination of experimental error and instrument accuracy is very likely to mask any actual difference between the two resulting values.So, at mains' frequencies, the difference between AC resistance and actual (DC) resistance would be very difficult to determine with any degree of accuracy.


What is the difference between in ac and dc powwer cable?

There is no difference in the cables. The only difference is the type of electrical power being transmitted. AC or DC applications use the same wires.


What is the difference between ac and dc grounding?

The difference AC and DC grounding is that AC is alternate current and DC is direct current. Grounding for both AC and DC is the same.


What is the difference between AC and AD?

AC is alternating current and AD is Anno Domini or after Christ.


Why is AC meggering not used?

You do not use AC to megger a device, because the purpose of meggering is to measure the insulation resistance of the device. You use DC to do that. If you used AC, you would be unable to differentiate between insulation leakage and capacitance.

Related Questions

What is a difference between DC and ac resistance and expline DC resistasce?

DC is just direct current into a resistance it is a linear function. AC if the resistance is non reactive it would be the same linear function.


What is the difference between DC and AC resistance?

AC resistance should NOT be confused with IMPEDANCE or REACTANCE.When AC flows through a conductor, it tends to flow towards the surface of that conductor due to a phenomenon called the 'skin effect'. The skin effect, therefore, acts to reduce the effective cross-sectional area of the conductor. Since resistance is inversely-proportional to cross-sectional area, the result is an elevated value of resistance compared with that to DC current. This is called AC RESISTANCE, and it increases with frequency. At mains frequencies (50/60 Hz), AC resistance is not dramatically higher than DC resistance but the difference becomes significant at high frequencies.Read more in the Related link shown below this answer.


What is the difference between AC and DC choke?

There is no difference between AC AND DC chockes


What is the formula to calculate AC resistance if the DC resistance is known?

AC resistance is the term used to describe the elevated value of resistance due to the reduction in a conductor's effective cross-sectional area due to the the skin effect caused by an alternating current. The skin effect describes how AC current tends to flow towards the surface of a conductor, rather than being distributed across the entire cross-sectional area as is the case for a DC current.For 50/60 Hz supplies the skin effect is not great and, so, there will not be a great difference between the DC resistance and AC resistance of a winding. Accordingly, it will be very difficult to calculate the winding's AC resistance, as its value is likely to be masked by experimental error and the accuracy of the instruments.In theory, by using a wattmeter and an ammeter, the resistance of a load -in this case a winding- the readings can be inserted into the equation: R = P/I2. Using a DC supply will reveal the (DC) resistance value, and using an AC supply will reveal the AC resistance value. As explained, a combination of experimental error and instrument accuracy is very likely to mask any actual difference between the two resulting values.So, at mains' frequencies, the difference between AC resistance and actual (DC) resistance would be very difficult to determine with any degree of accuracy.


Why ac current attract?

As we touch an ac supply in which due to body resistance , we create a phase difference between the ac supply and us . As ac reverses polarity , so do we , but our polarity change is opposite to that of the polarity change of ac supply , hence our body gets attracted to the ac supply .


What is the difference between AD and AC?

Ad is higher than ac


What is the difference between in ac and dc powwer cable?

There is no difference in the cables. The only difference is the type of electrical power being transmitted. AC or DC applications use the same wires.


What is the difference between ac and dc grounding?

The difference AC and DC grounding is that AC is alternate current and DC is direct current. Grounding for both AC and DC is the same.


What the difference between AC and DC?

AC rises with respect to time but DC is steady.


What is the phase difference between the current through the resistor and inductor in an AC circuit?

The phase difference between the current through the resistor and inductor in an AC circuit is 90 degrees.


What is the difference between AC and AD?

AC is alternating current and AD is Anno Domini or after Christ.


Difference between first class and first class ac in railways?

No much difference between first class and first class ac. Only AC is the difference. First class does not have AC.