https://stream.echo6.co/videos/watch/f4b613e0-5340-4ea8-8608-90bf77bbb92c Story time. A very long time ago I was gazing in the shop windows of a large Glasgow department store called Lewis's. They had some unusual illuminated tubes in the window that had a plug-in power supply and a coiled cable leading to a very narrow plastic tube with a neon tube inside it. I asked a shop assistant if she knew where they got them from and she contacted the window dressing team who took me up to their workshop. They said they had been a bit unreliable and gave me a faulty one, warning me to be careful as one of their crew had received an electric shock from the wires while it was unplugged. Inside the plug was a circuit board potted in deep resin to hide the components. It had two spade terminals at either side - mains in and high voltage out. The label indicated which terminals were which and also gave a footage range for the neon (actually argon/mercury) tube. These units may have been made by Masonlite - a big player in neon sign components. I reverse engineered the circuit, carefully digging away at the resin to reveal the hidden components. Once I'd worked out the circuitry I started experimenting with DIY versions, and got some custom tubes made by a Glasgow based company called The Neon Workshop. It was always a pleasure visiting the Neon Workshop, as Donald the manager was a veteran of Glasgow's sign industry when it had competed with Las Vegas for big animated skyline signs made by a company called Franko Signs. It was interesting hearing about the older technology used in them. Running tubes on a DC multiplier does have some disadvantages. It restricts the length that can be run, only seems to work properly with mercury based tubes and has a side effect of causing mercury migration where the mercury vapour in the tube gradually moves to the negative end and either needs the polarity reversed, or the bead of mercury shaken back to the other end. The upside is that it is a very simple and cheap circuit that can be made with ordinary components. I've seen these used in some of the neon radios that were popular for a while. The clear case had the multiplier circuitry in full view. The use of multipliers also allows very simple circuitry to be used to animate short sections of tubes. I made a prototype module with four multipliers and opto-triacs that could connect to my fairground lighting control system. Note that the circuit I show in the video is a very basic 240V circuit suited to about 2' (600mm) of 12mm diameter tube. Using a longer tube may result in striking/flickering issues and a shorter one will put extra strain on the current limiting resistors. For 120V use or longer tubes it will be necessary to increase the number of multiplier stages with beefier capacitors for the first few stages and then a decent number of the 10nF capacitors to get the strike voltage. Treat the output as high voltage referenced to the mains supply. To quote a dutch friend (Dirk Boonstra) touching the output of these power supplies will blow all the hair out of your head. I used to use double insulated meter lead wire to connect to tubes with crocodile/alligator clips (while the power was on!), so it's a miracle I didn't get zapped. This circuit is presented for personal experimental use only. It's not really suited to commercial use, especially with the common availability of electronic neon power supplies. The DC mercury migration effect is what I was aiming for in the "M" tube. It has a deliberate dip in the middle to hold a droplet of mercury in an attempt to do a colour split when the mercury migrates through the neon carrier gas. Where just the neon is present the tube glows orange, but when the mercury vapour is present it glows blue. It works, but takes a VERY long time for the migration to occur. Although using the same science as a germicidal UVC tube, no significant amount of UV escapes from this tube due to the natural blocking characteristic of soda/lead glass. Compared to modern high frequency electronic power supplies, the simple DC multiplier produces much less electrical and RF noise. Possibly part of the reason they were used in the ornamental neon radios. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- http://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty. #ElectronicsCreators Wed, 15 Apr 2026 09:46:12 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://stream.echo6.co https://stream.echo6.co/client/assets/images/icons/icon-512x512.png https://stream.echo6.co/videos/watch/f4b613e0-5340-4ea8-8608-90bf77bbb92c All rights reserved, unless otherwise specified in the terms specified at https://stream.echo6.co/about and potential licenses granted by each content's rightholder.