1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How does a negative ion generator work?

  1. Mar 10, 2007 #1
    Like this one:


    I understand that it uses some sort of "needle assembly," and electric fields are stronger at sharp points in a conductor and then will ionize the surrounding air at a certain potential. But how exactly are the negative charges isolated in the first place? Some friends and I have discussed how this might happen, such as first charging a capacitor, then attaching the negative lead to such a needle assembly, then grounding the positive lead, but we're not exactly sure.
    Last edited: Mar 11, 2007
  2. jcsd
  3. Mar 12, 2007 #2


    User Avatar
    Gold Member

    I believe the ionisation is caused when an electron binds loosely with a gas molecule. If you put a high -ve voltage on a needle, electrons can escape from the point.

    That's about right. The voltage can come from any source, with the +ve grounded.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook