Air is normally an electrical insulator; electricity cannot jump out of a wall socket and shock you because the surrounding air does not conduct it. All insulators, however, break down under extremely high voltages. At these conditions, the voltage strips electrons from the atoms in air, forming ions of nitrogen and oxygen, which conduct electricity. The actual process is complex, affected by pressure, humidity and the complex movements of gas molecules. Lightning, for example, forms jagged spikes and arcs instead of straight lines. To calculate the voltage for electricity to jump across a spark gap, you can use a simple formula.
Instructions
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1
Turn off all power to the spark gap apparatus.
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2
Measure the distance in centimeters between the electrodes in the spark gap with the ruler.
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3
Key in the number of centimeters into the calculator. Press the multiply key. Enter 30,000. Press the equals key. The result is the voltage required to produce a spark in the gap. For example, if you measure 3 centimeters, 3 x 30,000 = 90,000 volts; the breakdown field for air is 30kV/cm.
