0
\$\begingroup\$

I am trying to figure out AWG from a European/German schematic. The wire is listed as 0,3mm. (That's 0 (comma) 3mm.) I can find wire for sale in this diameter, but I need a reference to AWG. Is anyone familiar this measurement? The circuit is two parallel 807 vacuum tubes. The wire mentioned above is to wind a parasitic suppressor in both of the plates of the tubes. Thanks.

\$\endgroup\$
0
\$\begingroup\$

28.5AWG is exactly 0.3mm diameter. Not every manufacturer produces half sizes, and for most inductors it won't be that critical to be off half a size either way. For fill calculations (if it's a toroid or closed core) you need to be looking at the size over insulation, and not the nominal, and that will depend in the covering you choose. Carefully hand-wound parts may get away with thinner coatings that would be damaged by the forces involved with machine winding.

https://essexwire.com/sites/essexwire.com/files/2017-08/Essex-Wire-Engineering-Data-Handbook-EN.pdf

\$\endgroup\$
  • \$\begingroup\$ Thanks Phil. With two 807s in parallel, it's going to be approximately 75mA, 500V on each suppressor that I'm building. They will be wound around a 100 ohm carbon resistor. This seems like very small wire, but the diagram is proven (supposedly.) Any thoughts? Thanks again. \$\endgroup\$ – McMurdo Feb 12 at 2:10
  • \$\begingroup\$ If it's a single layer wind, the only voltage the wire sees is the turn to turn, unless there are some very high frequencies, if there are multiple layers it'll be higher. Can't you find a ready-made inductor? This seems not to be that special. \$\endgroup\$ – Phil G Feb 12 at 14:44
  • \$\begingroup\$ Ok, thanks Phil. For a parasitic suppressor, they specify to wind the coil around a 100 ohm, carbon composition, 1 watt resistor. I'm not sure why, but the diagram is very specific. Here's a link to the diagram, the suppressors are in the plates of the 807s. dropbox.com/s/ehp6tud66x3cw3d/MorningStar%20original.gif?dl=0 \$\endgroup\$ – McMurdo Feb 13 at 16:27
3
\$\begingroup\$

0,3 mm in English is 0.3 mm.

A Copper Wire Table tells me that #28 wire is 0.321 mm, and #29 is 0.286 mm.

\$\endgroup\$
  • \$\begingroup\$ Thank you Peter. I was confused as to if the 0,3 was referring to diameter or mils. Thanks for your answer. \$\endgroup\$ – McMurdo Feb 12 at 2:07
1
\$\begingroup\$

There are online AWG-metric conversion sites. A comma in Germany shows the decimal place. You also should be able to figure out a safe wire size knowing the maximum plate current (e.g. from the power supply transformer rating). Somewhat larger-diameter wire is acceptable, and may be preferable from a mechanical standpoint.

\$\endgroup\$
  • \$\begingroup\$ Thank you! My confusion was if the 0,3mm was saying it was .3mm diameter, or .3mm circular mils, which would be 22 gauge. \$\endgroup\$ – McMurdo Feb 12 at 2:05

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.