Re: Solid-State Marx (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: <sroys@xxxxxxxxxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 18 Jul 2005 15:21:24 -0700 (PDT)
From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Solid-State Marx (fwd)

Though I've never tried it, I've heard snails and
slugs won't cross copper. It apparently "shocks" them.
I think it should be in contact with moist soil. Maybe
you could try a piece of copper ribbon and surround a
snail and see if he will cross it. If not, simply
create a border around your garden of copper ribbon.

Adam

--- High Voltage list <hvlist@xxxxxxxxxx> wrote:

> Original poster: <sroys@xxxxxxxxxxxxxxxxx>
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Mon, 18 Jul 2005 14:08:20 +0930
> From: Matthew Smith <matt@xxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Re: Solid-State Marx (fwd)
> 
> Thanks to all who replied on this thread; all
> comments considered and
> taken on board.
> 
> 1) I like the diode idea from the defib.  Is this
> the Fitch
> configuration that Jim mentioned?
> 2) The repetition rate is low - triggering is
> manual.
> 3) I don't know what the instantaneous current is
> because I don't know
> what the load resistance will be; I'm a little
> concerned about the ESR
> of the caps - would a heavy discharge through a
> string of them cause
> them to 'pop'?
> 
> I suppose I should have explained myself better in
> the first place, so I
> will now set out what I'm trying to do and why:
> 
> I have a problem with snails; this area gets lots of
> small, white
> snails.  They come in plagues and cause all sorts of
> problems for the
> grain farmers, getting in the crop and damaging
> augers and other
> transfer equipment.  My problem is snails in my
> vegetable garden.  I
> can't use poison - we have dogs.  My most effective
> way of dealing with
> them is picking them up one by one and whacking them
> with a half-brick -
> not very elegant, time consuming and requires a lot
> of bending over.
> 
> My idea (and I'm sure to get hate mail now from the
> Mollusc Protection
> League) was to have an HV source built into a wand
> (PVC conduit) with a
> couple of electrodes, about a snail's width apart. 
> A manual trigger at
> the top would dump a few Joules through the snail,
> cooking it.  (Sadly,
> these aren't the sort that can be served with garlic
> and herb butter.)
> 
> Idea #1 was to use just a disposable camera flash
> mechanism and dump the
> 250-300V from the cap straight into the snail, but I
> thought that there
> would be insufficient voltage to puncture the shell,
> even if one of the
> contacts was on the "wet end".  That's when I got
> the idea of the
> photo-flash Marx bank.
> 
> You know, I had never actually pondered the workings
> of solid state
> relays before and certainly didn't realise that they
> used a photovoltaic
> device (I always assumed that gate drive was
> acquired from the line
> somehow.)   The photovoltaic solution is certainly
> one way to get power
> to the gates - the biggest problem in my mind.
> 
> I have two or three SSRs on my bench - I may do a
> test on this.  They
> must be rated up to 340V DC if they are running on
> 240V AC, so would be
> of roughly the same voltage rating as the caps. 
> 1N4007s can handle the
> charging for me so I could conceivably run the whole
> thing off a 4 cell
> NiMH pack.  I would be at least 10 seconds between
> snails (note: must
> wear goggles in case of flying shell shrapnel), so
> charge rate wouldn't
> need to be that high.
> 
> Time for some experimentation next weekend.
> 
> Cheers
> 
> M
> 
> 
> -- 
> Matthew Smith
> South Australia
> http://www.kbc.net.au
> 
> 
> 
> 



		
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