Aerospace Engineering Department
BS in Aerospace Engineering
This report observes and analyzes the effect the pressure and gap distance have on the minimum positive breakdown potential between two parallel plate copper electrodes in both air and CO2. Two gap distances, 0.57 cm and 2.44 cm, were used. Paschen Curves generated in air from these distances had a strong positive correlation with a Spearman correlation coefficient of 0.97. Curves generated in CO2 had a Spearman correlation coefficient of 0.87. The strong correlation for both gases verifies Paschen's Law. The minimum breakdown potential in air was 361 ± 2 V at a pressure x gap distance of 0.55 ± 0.01 Torr cm. The minimum breakdown potential differs from published data by 2%. The pressure x gap distance differs from published data by 17%. This verifies the Cal Poly Paschen Breakdown Apparatus and procedure. The minimum breakdown potential in CO2 was 540 ± 20 V at a pressure x gap distance of 0.5 ± 0.1 Torr cm. The minimum breakdown potential differs from published data by 4%. The pressure x gap distance differs from published data by 67%. Differences between the pressure x gap distance results and published data suggest that electric field concentrations present at the edges of the electrodes cause the apparatus to behave as though the electrodes are closer together.