3 ms·
Can someone explain why the electrodes have to be sharp? Intuitively it feels right, but what is the actual reason? As far as I can see, the challenge is to g
by adrianratnapala 8y ago
Can someone explain why the electrodes have to be sharp? Intuitively it feels right, but what is the actual reason?
As far as I can see, the challenge is to get the E-fields (aka voltage gradients) high enough that electrons can easily leave the metal. But for that you need the electrodes close to one another, but they don't have to be sharp.
I suppose if you have too big an area of metal at near-contact, then you will get unwanted capacitance. But is that the only reason?
- zamalek 8y agoError margins? There's a lot more room for error with a flat surface. I'm not sure if that level of precision is at all important, but it's my best guess.
- okl 8y agoProbably, because it results in a higher field strength at the tip, see https://www.physicsclassroom.com/class/estatics/u8l4d.cfm#p8 https://www.physicsclassroom.com/class/estatics/u8l4d.cfm#p8
- murbard2 8y agoThey do have to be sharp. As an exercise, consider a metallic cone with a charge of 1 and look at the distribution of the charge that minimizes the electrostatic energy. You will find that the charge collects near the tip of the cone. In general, charges will collect where the curvature is high. It's easier to push electrons out of a pointy tip (or inside of a pointy tip) because they are denser there.
- YetAnotherNick 8y agoApart from other answers, I think cold welding might be one reason too.