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Gold or Silver which is the better electrical conductor?
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Q. I once read that Silver is a better conductor of electricity than Gold, the problem with silver however is that it is very rigid and tarnishes very easily. Am I correct?
Wellsley Over- Johannesburg, Gauteng, South Africa
+++++A. Yes you are correct.
Good luck!
Goran Budija
- Zagreb, Croatia
+++++A. Also better than gold is copper. Metals are nature's better conductors. Of course modern physics has invented (or should I say discovered?) superconductors. Zero resistance and they're not even metals.
Guillermo Marrufo
Monterrey, NL, Mexico
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Q. So, silver is a better conductor than gold but because it's not smooth and builds up a tarnish, the gold is better in the long run? well the original question is if silver is a better conductor why do they use gold on cars' electrical components?
Justin Hansenase certification - Ogden, Utah, USA
+++++A. You have to look at two different things, Justin: the resistance of the solid material that is the conductor, and the resistance of the joint (or connection / contact surface / interface, or whatever you want to call it). Silver has higher conductivity (lower resistance) than gold. But it tarnishes, which means a high resistance oxide forms on its surface. Silver is fine for many things, but where a very low voltage and low current is involved (for example in electronics signals) the tarnish can interfere with the signal and gold must be used instead.
Ted Mooney, P.E.
finishing.com
Brick, New Jersey
July 23, 2008A. Silver is the best conductor,but usually not used due to expense. It would not surprise me to see it used in integrated circuits someday however,like copper is now (and aluminum is/was). The difference isn't a lot,but 5% is 5%.
Tarnish could be a problem for high frequencies where skin effect becomes critical
As for superconductors, most of the commonly used ones are in fact metals. A common one is an alloy of niobium and tin. The metallic ones are used for two reasons. First, wires can be easily made and coils easily wound. This on its face wouldn't be a deal breaker. You can easily imagine depositing films of superconducting material on drum,etching it,adding a insulating layer and repeating,thus creating a large number of windings.
The real problem is that the high temperature superconductors lose that property in high magnetic fields,which happens when you use them with high currents. The low temperature superconductors do this too,but at much higher currents so they are more useful. (Super conductors are mostly used for very high powered magnets)Tarnish on silver could become critical for applications where skin effect was important (high frequencies). In fact, in high powered RF amplifiers coils are often made from copper tubing and gold plated. Although gold is not as conductive as copper it is resistant to corrosion. If the layer is thin compared to the thickness of the layer the current flows in,most of the current will flow in the copper anyway.
Michael Michalski
If skin effect was the only issue with silver,then we could find ways to deal with that. The easiest way to deal with it would be to deposit a thin layer of a inert material (alumina?) on the surface to prevent corrosion. If it was thin and robust enough,it could prevent corrosion while still transferring enough heat and not increase the size of the wire. The final answer comes down to cost. A silver wire would cost over 100 times a copper wire. While it might be useful in a semiconductor chip,where the actual cost of the silver would be very small compared to the cost of the chip, in a speaker cable it would be prohibitive (in a satellite, spacecraft, or weapon system, it might be ok, if the benefits justified it.)
- Kent Ohio
July 22, 2010
Q. Why aluminium is a better conductor when its resistivity is higher than gold?
Gary Low- Subang Jaya, Selangor, Malaysia
July 22, 2010A. Hi, Gary. If it's resistivity is higher, then it's conductivity is lower by definition. However, "better conductor" is very loose terminology. Maybe "better" per unit of weight, maybe more current-carrying capacity per dollar spent, etc.
Regards,
Ted Mooney, P.E.
finishing.com
Brick, New Jersey
January 31, 2012
! Don't know if what I do is legitimate methodology, but when I am building Antenna's, particularly high frequency stuff. I make the elements, waveguide, feedhorns etc. out of copper, then electroplate them with silver, and then a thin layer of gold on top to prevent the tarnishing of the silver. I don't have the time, or equipment to do precise measurement to see exactly what effect this has on the overall efficiency. I just figured that structurally the copper is good and easy to work with and cheap compared to the silver of gold. I figured that the silver plating would provide excellent characteristics considering the skin effect of UHF. Then to get away from the tarnish issue decreasing the conductivity of the silver, I plate a very thin layer of gold on top of the silver. I may be wrong but I felt that this should give one pretty close to the cost of the copper, with the conductive characteristics of silver and the non tarnishing characteristics of the gold. Maybe some one can tell me if the gold plate on top of the silver eliminates the conductivity of the silver? If so then the silver plate is a waste and one would be better off just plating a thin layer of gold on the copper. From what I can see it seems to work quite well, but then I reckon the gold would.
Leonard Legg
- Durango, Colorado, U.S.A.