dangers of high voltage and measurement  - Page 1
Forum section: electronics / beginners

author: waspinator
author_rank: Contributor
timestamp: May 03, 2016, 12:08:33 am
content: Hi,I recently saw Julian's Postbag which featured a high voltage (400kV) step up converter and was wondering the effects it would have if you passed that voltage through yourself, and how you would go about measuring it. Would it be painful and/or damaging? It couldn't be fatal could it? I'd imagine that the current would be very very low, and from what I understand current is the bit that's dangerous, not voltage.Thanks

author: Brumby
author_rank: Unknown
timestamp: May 03, 2016, 06:00:56 am
content: In short, yes this thing could kill.While the average current at 400KV would be less than 30uA, it could potentially deliver 10mA at 1KV if loaded appropriately. Note - these areaveragecurrents, but the unit is described as beingpulsed, so if the pulse equates to a 10% duty cycle, you could be looking at pulses of 100mA at 1KV.The flow of electricity through the human body is not easily defined. It is dependent on a number of variables, but make no mistake - theabilityof this device to deliver a fatal shock is real. Treat it with respect.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: May 03, 2016, 06:21:49 am
content: While that output is sort of impressive for the small separation of the wire ends, I seriously doubt if the thing can actually get up to 400 kV and survive itself. At those voltages, tiny plastic insulation is essentially meaningless. Just take a look at how voltages of a tenth of that or even less are handled inside a CRT monitor or television set (remember those?).I'd like to see a demonstration of that unit with the output wire ends connected to metal balls separated by 10 cm.

author: Brumby
author_rank: Unknown
timestamp: May 03, 2016, 07:17:02 am
content: If you read the descriptions on some of those units, they say not to have a gap of more than 10-20mm and "Do not exceed the maximum arc distance electricity, energy can not be released due to high pressure, can easily damage the module."They are well aware of the potential for this thing to self destruct.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: May 03, 2016, 08:54:06 am
content: Quote from: Brumby on May 03, 2016, 07:17:02 amExactly. So how can the claim be legitimate that it produces "400kV" if it self-destructs at 60 kV? Under what circumstances can it reach 400 kV without self-destructing?

author: Brumby
author_rank: Unknown
timestamp: May 03, 2016, 12:57:22 pm
content: You have made a couple of assumptions there - but you may be right.Anyone here who plays with this stuff?

author: Martini
author_rank: Regular Contributor
timestamp: May 03, 2016, 09:28:41 pm
content: Quote from: Brumby on May 03, 2016, 06:00:56 amWhat if you run it on a coin cell, then?

author: langwadt
author_rank: Super Contributor
timestamp: May 03, 2016, 09:47:06 pm
content: Quote from: blueskull on May 03, 2016, 09:36:18 pmthere is no way that that thing has anyway near enough isolation distance inside, outside or anywhere else to handle"hundreds of kV"

author: Martini
author_rank: Regular Contributor
timestamp: May 03, 2016, 09:52:33 pm
content: Does that make it somehow more dangerous?

author: Augustus
author_rank: Regular Contributor
timestamp: May 03, 2016, 09:58:10 pm
content: Should be sufficient for a diy mosquito zapper projectJulian is a wimp, Big Clive would use his tongue to measure the output voltage of this device

author: waspinator
author_rank: Contributor
timestamp: May 03, 2016, 11:12:05 pm
content: It's amazing how a 18650 cell can become so dangerous. and that the device only costs ~$2. What's the best way to measure the waveform? I assume you need some expensive probes. I wonder if Dave would be willing to do an experiment with this. Does writing @EEVblog ping him?

author: joeqsmith
author_rank: Super Contributor
timestamp: May 04, 2016, 01:41:28 am
content: Quote from: waspinator on May 03, 2016, 11:12:05 pmYou could look at what North Star has to offer. Your converter is running outside anything I have tried to measure and I am sure brings a whole bunch of problems. I have made some capacitive divider probes that I used in the 40KVish range. No reason this would not work. For wide band down to DC, the best probe I made will work to around 60KV. Maybe have a look at Pearson as well.Imagine a $7000 probe to look at a $2 device. Maybe throw an extra scope in there in case something goes wrong....Good luck. Post what you come up with.

author: waspinator
author_rank: Contributor
timestamp: May 23, 2016, 03:52:26 pm
content: Just saw a video of someone touching an arc from a lighter. not sure how much voltage runs through the arc lighters, or how comparable they are to the module, but they don't seem to have real effect.