24 ms·

Do tell.

• robocat 4y ago
  First example vid I found using those keywords: https://m.youtube.com/watch?v=kXaOP8O4HpI https://m.youtube.com/watch?v=kXaOP8O4HpI
  • djmips 4y ago
    Which seems to show that you use the pencil graphite as an electrode and spark it to ground. The 'fatness' of the spark determines the polarity.
  • userbinator 4y ago
    Written description: https://navyaviation.tpub.com/14329/Figure-6-52-One-Method-Of-Checking-Coil-Polarity-287.html https://navyaviation.tpub.com/14329/Figure-6-52-One-Method-O... ...although I haven't found any explanation online why it works. This method has probably been known for over a century, so I suspect it may be in some old physics books.