Wire Table
Units are a mess when it comes to coiling - long after UK has gone metric the former colonies still stick to imperial units! To make it worse there are two wire gauges standards British swg and American which are not quite equal. Inductance formula's require measurements in inches, the calculator programs work out wire lengths in feet. We buy wire by the half kilo, they buy it in lbs. I have suggested that we move everything metric but will they listen.....
Meanwhile this table might help, or it might not!
|
USA awg |
UK swg |
metric
dia mm |
meters
per 0.5kg |
feet
per 0.5kg |
turns
per inch |
Amps | resistance
ohms/1000ft |
| 32.00 | 36.00 | 0.20 | 1850 | 6086 | 125 | 0.05 | 167.30 |
| 30.00 | 33.00 | 0.25 | 1120 | 3684 | 100 | 0.08 | 105.20 |
| 28.00 | 30.00 | 0.32 | 705 | 2321 | 79 | 0.12 | 66.17 |
| 26.00 | 27.00 | 0.40 | 438 | 1439 | 63 | 0.19 | 41.16 |
| 24.00 | 25.00 | 0.50 | 280 | 921 | 50 | 0.30 | 26.17 |
| 23.00 | 24.00 | 0.56 | 223 | 734 | 45 | 0.38 | 20.76 |
| 22.00 | 23.00 | 0.64 | 170 | 558 | 39 | 0.50 | 16.46 |
| 21.00 | 22.00 | 0.71 | 139 | 457 | 35 | 0.61 | 13.05 |
| 20.00 | 21.00 | 0.80 | 109 | 360 | 31 | 0.78 | 10.35 |
| 18.00 | 19.00 | 1.00 | 70 | 230 | 25 | 1.21 | 6.51 |
| 16.00 | 18.00 | 1.25 | 45 | 147 | 20 | 1.89 | 4.09 |
| 15.00 | 17.00 | 1.50 | 31 | 102 | 17 | 2.72 | 3.25 |
| 14.00 | 16.00 | 1.60 | 27 | 90 | 16 | 3.10 | 2.58 |
| 12.00 | 14.00 | 2.00 | 18 | 58 | 13 | 4.84 | 1.61 |
DC Wire Resistance against diameter in mm
While this is interesting it is not the whole story first of all the AC resistance is higher than the DC resistance because of the skin effect - (see the transformer page). Plus resistance is only one of the sources of loss - there is also the effects of inter turn capacitance, eddy losses and ionisation losses all of which take energy out of the system and add to the effective impedence - lowering the Q.