5D40.63 Plasma Column

Electricity and Magnetism» Resistance» Conduction in Gases

5D40.63 Plasma Column
Before moving the plasma column, detach the banana plug connector under the column from its high-voltage power supply. Hold the glass column in one hand and, with the other hand under the separate wood/pvc platform, lift the column and platform together. CAUTION: Before reconnecting, ensure there are no conducting surfaces or other cables near the HV cable to cause arcs. Short-circuits through the cable insulation will damage the power supply. Plug the green ground into the ground jack of an AC outlet. Use the control on the HV supply to vary the input to the column and demonstrate the affect on arc length.

Comments

A fly-back transformer power supply injects 15-kV, 50-kHz current at one end of the column. 0.1-atm argon and neon gas create a path of lowest resistance for the discharge which extends to the far end of the column. The return path is by capacitive coupling through the glass to the air or objects placed close to the glass. The column is also useful as a spectral source. View the visible argon and neon spectra in a darkened room using hologographic gratings handed out to the students.

Apparatus

4-foot long Neon and Argon Plasma Column

15-kV, 50-kHz Power Supply

Michael --Thomason 07:41, 16 May 2007 (UTC)