Breakdown paschen curves

Fig. 9.18 Breakdown voitage U between paraiiei eiectrodes in a homogeneous eiectricai fieid as a function of gas pressure p distance between eiectrodes d (in mm) (Paschen curve), for air.

The conditions for gas breakdown in an electrical field can be described in terms of the breakdown voltage as a function of the product of pressure and gap spacing. The resulting graph is known as the Paschen curve... 

In other words, if M 11. This relation allows the determination of the breakdown voltage of the system, as given by the Paschen curve. 

Townsend Mechanism of Electric Breakdown and Paschen Curves... 

Here C = In - lnln( - -1) is almost constant. The breakdown voltage dependence on the similarity parameter pd is usnally referred to as the Paschen curve (Fig. 4-2 Raizer,... 

Figure 19.4. Paschen curves for air, nitrogen and sulfur hexafluoride from Husain, E. and Nema, R.S. - Analysis of the Paschen curves for air, N2, SF using the Townsend breakdown equation IEEE Transactions El-17 (4) 350-353. Copyright 1982 IEEE and used with permission.

For dry air the Paschen s curve has a minimum at pd =6.65mbar.mm corresponding to a breakdown voltage of 360V (Schaffert R.). If the air gap field creates a voltage less than the breakdown voltage for the particular discharges will not occur in the gap. When the... 

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