I would like to know how to predict electrical parameteres like voltage and current to create the electric arc between two graphite electrodes. As I know from literature this parameteres are 100 A and 50 V, however I do not know where they come from and how they are related. When electrodes are close enough 30 V drop is observed and plasma appears. Maybe is just something easy what I cannot understand.
Thank you for your help.
I think if you consider voltage-current discharge curve for air, and in other hand consider thevinin circuit curve consequently, these two curves have contact each other in two points that the stable point is the point with larger current value.
Hello Kasia Walczak
Hopefully I am not misunderstanding, but the voltage necessary to initiate an electric arc between two electrodes separated by a gas is given by Paschen's law.
https://en.wikipedia.org/wiki/Paschen's_law
For small gaps, the breakdown voltage is a function of thegap distance and pressure. An electric field of 3 kV.mm-1 is typically sufficient to cause break down of air.
I agree with the Joules Lloyd. Any electric discharge is governed by the Paschen's law. For creating the arc discharge first electrodes are touched and then separated slowly. During this time breakdown takes place. During breakdown threshold voltage are high whereas after breakdown electric current becomes high.
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