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From: Greegor on 5 Jul 2010 19:14
On Jul 5, 5:15 pm, Michael <peek...(a)gmail.com> wrote:
> I'd like to extend a very big thank you to everyone who has taken the
> time to respond to my original post.  I've enjoyed reading every
> response posted.
>
> Although I'm sure this next question will likely draw some criticism,
> I'd like to gather opinion on how to calculate a suitable sized grid
> for this circuit.  I suspect wire type, gauge and length are valid
> considerations and will have a bearing on the size (amps) of
> transformer required.
>
> Perhaps to start I need to determine the total length of wire in the
> grid and calculate it's resistance.  Add in the resistance of the
> resistors in the circuit.  Calculate amps required based on total
> resistance of the circuit and grid.
>
> Thoughts?
>
> Circuit:
>
> https://docs.google.com/leaf?id=0ByeTqxcQsAnPNGMxNTFmODUtODI5NS00ZmEx....

http://www.play-hookey.com/ac_theory/ps_v_multipliers.html

Is there any theoretical limit to these
voltage tripler diode capacitor ladders?

Aren't HUGE versions of these used for
some big lab stuff?

Huge safety liability aren't they?
From: IanM on 6 Jul 2010 07:37
Greegor wrote:
> On Jul 5, 5:15 pm, Michael <peek...(a)gmail.com> wrote:
>> I'd like to extend a very big thank you to everyone who has taken the
>> time to respond to my original post. I've enjoyed reading every
>> response posted.
>>
>> Although I'm sure this next question will likely draw some criticism,
>> I'd like to gather opinion on how to calculate a suitable sized grid
>> for this circuit. I suspect wire type, gauge and length are valid
>> considerations and will have a bearing on the size (amps) of
>> transformer required.
>>
>> Perhaps to start I need to determine the total length of wire in the
>> grid and calculate it's resistance. Add in the resistance of the
>> resistors in the circuit. Calculate amps required based on total
>> resistance of the circuit and grid.
>>
>> Thoughts?
>>
>> Circuit:
>>
>> https://docs.google.com/leaf?id=0ByeTqxcQsAnPNGMxNTFmODUtODI5NS00ZmEx...
>
> http://www.play-hookey.com/ac_theory/ps_v_multipliers.html
>
> Is there any theoretical limit to these
> voltage tripler diode capacitor ladders?
>
> Aren't HUGE versions of these used for
> some big lab stuff?
>
> Huge safety liability aren't they?

For any straight metallic wires, (I explicitly exclude coiled-coil
tungsten etc.) their resistance is negligible compared to the effective
source impedance of the multiplier chain and the resistance of the bug
about to be zapped. For any *reasonably* *thick* wires, their
resistance is negligible compared to the dynamic impedance of the
diodes, 'flash' capacitor (C7) and bug actually being zapped.

It comes down to durability, and ease of cleaning and of construction.
For ease of construction, its nice if they are solderable, and
durability requires reasonable thickness. Ease of cleaning requires a
linear grille rather than a mesh. Make a brass frame and solder 1.5 mm
or 1/16" brass rods through holes in two sides of it separated by
approximately 1 wingspan of the target insect. put a 'earthy'* grille
behind it offset by 1/2 the wire spacing and spaced by 2/3 the wire
spacing from the live grille and another 'earthy' grille in front of
double the spacing to cope with outsize bugs. Orient the grilles
vertically + raked forward for ease of cleaning.

It MUST be installed in an earthed metal box or non flammable insulating
enclosure tested to at least 3KV. It should not only be touchproof, but
it should be impossible to insert a standard pencil far enough to reach
its 'guts' That's at least 8". You need interlocks at least as good as
a Microwave has to disconnect the power and short C7 when the housing is
opened.

*'earthy' - an explanation. If any output terminal is hard grounded,
this device is truely lethal if anyone (e.g. a child) pokes a long
conductive object in there. If on the other hand you use an isolating
transformer with 2KV rated insulation to feed the points marked mains
230V and only connect the negative side of C7 via a chain of 2 high
voltage 1M resistors to ground or neutral, the possible current from
touching ONE terminal is limited to a much safer level.

You wouldn't see me building one except for installation over 10' above
the floor in an enclosed space with no access for untrained individuals.
(2 consecutive locked doors!)

If you are ever thinking of producing one of these for any place with
public access, even by trespass, you'd better work anonymously through a
chain of at least three shell companies located in the PRC, North Korea,
and Iran respectively!

Note: I have not given the ****ing obvious way of extending that circuit
at minimum cost for 120V operation, nor will I ever. You will have to
*REFLECT* upon it yourself . . .

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:
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