re:Re: How to calculate power supply bleeder resistor

Mariss,

(snips, inserts below)

>First off, 40VDC or 80VDC is not lethal.

BE CAREFUL HERE!
Although the likelihood of being electrocuted by 40 volts or 80v may
be less than a 220volt a/c jolt...

MANY accidents are "created" by the SITUATION, NOT the stimulus! What
I'm saying is, If you're rummaging around under your mill table and
unexpectedly "catch some volts", the REACTION is what gets ya!!! As
your body reflexively moves, you hit your head on the mill table, or
worse... i.e.,More people die from falls, than from what pushed 'em

Mariss mentions "withstanding" a CONTROLLED APPLICATION of 180vdc @
50ma. Our driver supplies range from 12 to 150vdc, BUT at TENS of
amps! And remember, the "theoretical human being" equivalent of
resistor and capacitor is just that: theoretical! (a cut or sweaty
skin can easily alter the "equation" seen by a body. As can the
LOCATION of the electricity entering the body.

For example: Many years back, I was going to bring to market
a "muscle stimulator". A pocket version of something which was used
on me during treatment for injuries in my athletic career. This was a
VERY simple circuit, 9v battery power. In "testing" the circuit on my
own body, I was able???! to send my own heart into arrythmia(uneven
beats), even though the amperage was minimal, to say the least.

This "only" happened if/when I put the electrodes in what could
safely be called a DUMB placement (customers may "always" be right,
but ARE NOT "always" Bright<g>, and product testing should simulate
this, IMO) Needless to say, "testing" was halted, I received a check
up from a cardiac specialist, and the product development was
stopped.

Other companies HAVE brought similar products to market since then.

I'm not trying to be alarmist here, and I do believe "common sense"
goes a long way. But be sure to think beyond the obvious, when safety
is concerned...

Hope this helps.

Ballendo

P.S. Mariss also wrote:

>Regards to discharging a cap. What drives you have attached will
>discharge it faster than any resistor.

I'm not sure what to say here? My linear supply without the bleeder
(drives attached) would hold charge far beyond that which occured
after the bleeder was installed.