Leonardo De Palo wrote:

> This apparatus, (reading the technical description) is able to
> generate a variable voltage between 200 and 800 Volt, with 45
> milliampere at 1 Mhz.

  That calculates to 36 watts maximum.  Since it is my profession, I can
tell you with some accuracy that that power level will burn a quarter
inch diameter hole in you inside of two seconds (or should that be
"inside of you"?).

  However, it is probable that it represents the short circuit current
limit, in which case the peak output power into the load calculates at
a quarter of this or nine watts.  That still does quite a bit of damage!

  In practice, the traditional method is to needle the hair follicle to
apply the current, requiring considerable skill and care.  The obvious
approach of applying the voltage to the hair itself is limited by the
fact that it is a rather good insulator.  It has a miniscule hollow core
however, so a high voltage may deliver sufficient power to destroy the
hair follicle.  I would expect the hair to burn out like a fuse at the
same time!  The danger is that such a high voltage can easily arc to the
adjacent skin, or the operator touch the skin anyway.

> The front panel has a timer and a couple pushbutton to increase or
> decrease the power at the tweezer.

  It thus sounds plausible that the timer is used to deliver a
single fractional-second burst with each depression of the trigger.
Diathermy "coagulation" current is indeed modulated, traditionally in
down-ramping pulses ("ringing" of a resonant circuit excited by large
impulses).  This contrasts with "cutting" current which is CW, throwing
sparks which explode individual cells on contact.  Coagulation just
cooks the tissue, but if strong enough, chars and burns it away.

  If there's a message in this, it is that there seems to be a major
S&M element in this depilation stuff, easily on a par with tattoo (but
then the good clinics do that too!).

> This device is powered from main line at 220 volt, and as you know any
> medical or paramedical device should be powered by batteries to avoid
> any potential injury to the patient

  You *could* power it by gel-cells to avoid a lot of problems with
isolation design and certification.  Although significant, the power
must, given the above considerations (e.g. pain), be limited to small
bursts at a time.  Usual trick is to use the same socket for the working
electrodes and the charger to guarantee only one function is used at any
one time.

> The spit out at the bikini-line of the hair is not my primary job,
> (I'm thinking to consider it) but I know the removal is not permanent.

  I'm not sure, Leonardo, whether your English is sufficient to have
twigged that the phenomenon referred to (in a "tongue-in-cheek" or
joking fashion) here was *accidental* pickup of hairs in the mouth
whilst engaging in an activity on the bikini line whose prime intention
was other than hair removal.

> My call of PIC DEPILATOR is for discuss about the value of the
> current,

  Controlled by controlling voltage

> the frequency (fixed or swept)

  *Must* be fixed, should be about 460kHz; there is a specification for
this.  *Not* 1MHz which is in the middle of the AM radio band and would
make you extrremely unpopular extremely fast.

  Using RF *does* make the transformers very light, but the reason for
using it is *actually* that there is no effect on tissue other than ...
heating.  The simple "do-it-yourself" electrolysis (correctly named in
this case) kits FWIW consist of a 9V battery, current limiting resistor,
grounding plate as part of the casing (grounding has not been mentioned
so far) and forceps or whatever.  To the extent that they might work, it
is by delivering a current too low to feel, for a much longer time.

  Cheers,
        Paul B.