Weird Science

Turning a Light Bulb into a Plasma Globe

Polish ver­sion is here

Cap­ti­va­ting Visual Display

A pla­sma globe is a device desi­gned pri­ma­rily as a visual novelty. It con­si­sts of a glass sphere fil­led with low-pres­sure gas, typi­cally a mixture of helium and neon, some­ti­mes with tra­ces of other noble gases. When acti­va­ted, rib­bon-like elec­tric dischar­ges form inside the globe.

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Wat­ching the con­ti­nu­o­u­sly moving, wri­thing ten­drils of elec­tric discharge cre­a­tes a mesme­ri­zing effect.

Ilustracja

The ope­ra­tion of a pla­sma globe is based on the phe­no­me­non of gas ioni­za­tion under high vol­tage. Inside the globe, low pres­sure allows ioni­za­tion to occur at rela­ti­vely low vol­ta­ges. The globe’s elec­trode is powe­red by a high-fre­qu­ency, low-cur­rent AC power sup­ply that gene­ra­tes about 10kV. The result is visu­ally stri­king elec­tric dischar­ges, with their color depen­ding on the type of gas inside. The dischar­ges rise upward due to convec­tion.

With some basic equ­ip­ment, you can build an impres­sive pla­sma globe at home using the same prin­ci­ples.

DIY Pla­sma Globe from a Light Bulb

To build your own pla­sma globe, you need a glass con­ta­i­ner fil­led with low-pres­sure gas. A stan­dard incan­de­scent light bulb meets these con­di­tions, as the inert gas inside the bulb is at suf­fi­cien­tly low pres­sure to pro­duce bri­ght dischar­ges. For the high-vol­tage source, you can use a  ZVS dri­ver or a Ruhm­korff induc­tion coil. Con­nect one ter­mi­nal of the high-vol­tage source to the bulb’s base, and gro­und the other ter­mi­nal.

War­ning: Using a ZVS dri­ver or other high-vol­tage sour­ces is not recom­men­ded for begin­ners without expe­rience han­dling high vol­tage. The device out­put can reach seve­ral tho­u­sand volts, posing a serious risk of elec­tric shock, which can be hazar­dous or even fatal. The author assu­mes no respon­si­bi­lity for any inju­ries or dama­ges resul­ting from buil­ding or using this device; pro­ceed at your own risk!

When powe­red on, bri­ght blue dischar­ges become cle­arly visi­ble inside the bulb. Tou­ching the bulb’s glass cau­ses the dischar­ges to con­cen­trate toward the point of con­tact. The effect can be seen in the photo and video below:

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The dischar­ges also emit a cer­tain amo­unt of ultra­vio­let radia­tion.

Enjoy your expe­ri­ments! :)

Fur­ther rea­dings:

Marek Ples

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