Repost - The how and why of failure...

From Sunday, January 25, 2009

The how and why of failure...

(Vocus) January 23, 2009: "...the taser deliver a high-frequency, high-voltage current..." (emphasis added).

This is an ideal opportunity to remind blog readers that the latest taser model in wide use, the X26 introduced in 2003, unlike the other previous high power taser (the M26 from 1999), has an output current waveform that contains a significant 19 Hz (low frequency) component.

It seems that everyone on both sides of the taser issue continues to assume that tasers are strictly (the safer) high frequency - but it is not true in the case of the X26 due to an often-overlooked DC-offset pulse after the arc phase.

This also has huge implications for the duty cycle - the low frequency component at 19 Hz and all related harmonics are 100% continuous duty cycle for the entire 5-second cycle.

So the X26 is both low frequency and 100% continuous duty cycle - both of which reduce safety independently (double effect) as compared to the older M26 (invalidating many older studies, as well as invalidating many of Taser's previous explanations for the root of their product's claimed safety).

Based on Taser's and Kroll's continued reliance on the "short duty cycle" (sic) and "chronaxie" (ditto) for their safety assumptions, and that they've apparently never admitted that the duty cycle of the X26 at 19 Hz is 100% continuous, it really seems like they forgot about the basics of Fourier transforms and the significant impact of that little DC pulse that they added to the X26 in 2003.

If they really do fail to understand why their 'harmless little taser' (sic) might be more dangerous than they previously calculated, then perhaps ignorance of Fourier is the reason why.

Even Kroll's late-2007 IEEE Spectrum article was still talking about "chronaxie" which depends on short pulses. This indicates that he failed to grasp that important detail.

It's another smoking gun (we've found others).

This important technical detail has, as far as I know, not been highlighted anywhere except on this blog.

See para 2 of this post 2008 - a year in review... [LINK] for an overview and links to the earlier posts where this technical details were first noted.

Then see the following three key posts:

Forgetting Fourier are we ? [LINK]

Guesstimated Spectrograms [LINK]

Up to end-September 2008 [LINK] (*)

(* Note the steep rise in the monthly taser-associated North American death rate, almost a step function, from less than one/month to about seven/month, starting in mid-2003 - strangely coincidental with the introduction of the X26.)

My conclusions about the spectrum and duty cycle implications of the little DC pulse added to the X26 taser can be reviewed and confirmed by any electrical engineer.


UPDATE:

As if this needed any further support, but consider this... The M26 has a peak current of about 15 to 18 amps. The newer X26 is only about 3 amps. But even Taser International's own analysis indicates that the M26 is safer (wider margin). What could explain this? Why is seemingly-less actually more? Hey, I've explained it above.