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Electronics => Projects, Designs, and Technical Stuff => Topic started by: mcinque on September 23, 2017, 04:59:15 pm

Title: +2 million Volts from a small self defense stun gun, plausible/needed?
Post by: mcinque on September 23, 2017, 04:59:15 pm
They claim 2.400.000 Volts (of course infintely small current, it's not specified how much).

Is this kind of voltage plausible/needed for a stun gun or is just for marketing? Do they have enough space/isolation to reach that voltage in a handheld product avoiding arcing and shock to the owner?

I've read tasers discharge 25 Watts of power at 50.000 Volts (and they're really effective!).
Title: Re: +2 million Volts from a small self defense stun gun, plausible/needed?
Post by: CatalinaWOW on September 23, 2017, 05:57:19 pm
There is another whole thread on this class of devices.  The advertising claims just keep climbing.  The only limit I see is the number of digits they can fit on the page with multipliers that the advertisers know.

https://www.eevblog.com/forum/chat/new-physics/msg1159399/#msg1159399 (https://www.eevblog.com/forum/chat/new-physics/msg1159399/#msg1159399)
Title: Re: +2 million Volts from a small self defense stun gun, plausible/needed?
Post by: Cerebus on September 24, 2017, 02:42:11 am
Ponder this: The approximate dielectric breakdown voltage of air is 3,000,000 volts per metre, for PTFE it is 19.7 MV/m, polythene is similar, so is PVC. That covers most of the common insulators you're likely to find in some electronics. Given that information you don't even need to do mental guesstimation to realize that something hand held isn't going to have enough room to isolate two conductors with a 2.4MV potential difference between them, even if it was made from solid plastic with no air gaps.

Edited to add: And don't even talk about creepage distances at 2.4MV - remember, you have to hold this thing to use it.
Title: Re: +2 million Volts from a small self defense stun gun, plausible/needed?
Post by: David Hess on September 24, 2017, 03:48:57 am
50kV~100kV pulse sounds more sensible for that size, cost and air gap distance.

Exactly, the voltage never gets higher because something, hopefully the air, breaks down first.  When using it on a person, the voltage is even lower and it operates more like a constant current or constant power source.