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Comment by jmwilson | Hacker News Reader

Most Nixie tube drivers can't hurt you, unless they are directly rectifying the mains. DC-DC designs that start with typical low voltage can give you a quick jolt but cannot sustain their rated voltage or current if you short them.

I designed my own Nixie tube driver last year, and documented it on Hackaday: https://hackaday.io/project/170962-nixie-tube-170-v-flyback-.... I think I had more fun building the power converter than with playing with Nixie tubes.

Unlike the NCH6300HV, it's an open source hardware design with complete design notes and files for understanding how a HV power converter works.

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So, once upon a time I had the unpleasant job to fix a large neon display for a trade show the evening before the trade show. It was supposed to be the center piece and major attractor for the booth that it was meant for. The guy that built it was quite clever with stuff like that, he'd taken a nixie based clock and used the output from that to drive a bunch of very high voltage triacs to drive the primary of the transformers powering the neon tubes.

Unfortunately, the evening before the event the clock failed and I was left to debug it while the other guy went to have some dinner. The 'ground' that I connected my scope to was at minus many KV and the resulting spark and flash were bad enough to evaporate the crocodile clamp. I thought I had gone blind, but the power had gone out. And not just in that building. I stumbled downstairs and called the other guy who said that at his place the power had also just gone out. The good news: I wasn't blind. The bad news: a good chunk of Amsterdam East was without power. Not a good day. And we didn't get to bring our fancy clock.

so, this is not nearly as dramatic, but I was at a busy hackerspace (新车间) swapping out the brains of an electric doorbell to replace the chime with an arduino sound trigger - crossed a wire while plugged into mains and the the whole 220v side of the doorbell explodes in sparks while a dozen people on their laptops are plugged into the same surge protector. No harm done, mea culpa. A more experienced hacker comes over with a huge bulky 1:1 transformer for isolating circuits and says “if you’re going to hack on mains, plug into this”

after some inspection of the burned circuitboard, I realized all the parts I need are on the undamaged 5V side of the board, so it worked fine on USB power anyway, but I was grateful for that hackerspace spirit of “that was stupid, here’s the tool you’re supposed to use“

Nice one. Yes, an isolation transformer isn't a luxury item. Good to see you didn't hurt yourself. I still have memory flash-backs whenever I hook up a crocodile clamp to something.

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