What limits the strength of a field at a given point in space?

[Crazymechanic]

Ok even though Vanadium recently asked me to stop this stupid way of learning something through asking the same questions , even though their not all the same , I'll try my cards with this one.Ok so we have fields like gravitational, electric and magnetic , now theoretically the fields don't have any upper limits of their strength at a given point in space if I understand correctly but practically what limits a fields strength at a given point of measurement ?
Okay take gravitational field of a black hole for example , according to our current understanding the field inside the event horizon goes to infinity as there is so much mass at such a infinitely small point, and because mass gravitates it can make up a field which is so strong.

(theoretically)Would it be possible to make a black hole using electric repulsion , attraction of charged particles which also have mass , like having an extremely strong say negative potential which would attract positively charged particles and crush them in a place so small that later on given enough mass of the particles it could turn into a black hole?

I ask this because gravity is much weaker as a force than electromagnetism , and if it takes a star of huge mass to later fall into a BH then why couldn't it take a much smaller mass of charged particles and a extremely strong negative potential to crush that into a BH.?

 

[jaydnul]

Try this: http://en.wikipedia.org/wiki/Reissner-Nordstr%C3%B6m_black_hole

 

[Drakkith]

Because charged particles have the tendency to repel each other.
Also, I notice that you do a lot of "handwaving" when you ask questions. For example:

like having an extremely strong say negative potential which would attract positively charged particles

See? You're skipping steps here. The fact is that we can't just have this crazy negative potential. It's literally not possible. To get this negative potential you want you'd need an imbalance of charges, meaning more negative charges in an area compared to positive. At best you'd attract enough positive charges to neutralize the negative ones and end up with plain old neutral matter. Try to work your way up to the question you want to ask. Understand what it would take to make the next step happen. A lot of times you can answer your own question this way.