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Re: [Distillers] For Rob - Switching (was) Re: Calm down children!

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  • Robert Thomas
    Wow! any chance of a diagram? Now, if you can just build the rest of the automatic cat sh*ts=cat burns device, I can stop hunting the net for solutions to my
    Message 1 of 29 , Apr 3, 2006
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      Wow!
      any chance of a diagram?
      Now, if you can just build the rest of the automatic "cat sh*ts=cat
      burns" device, I can stop hunting the net for solutions to my
      inhospitable garden problem (bigG).

      Cheers
      Rob.
      p.s. Yes, Harry I'm still here, despite what I said.


      --- Sven Pfitt <the_gimp98@...> wrote:

      > Use the 555 link that others posted, and build a timer with a 1
      > second time interval.
      >
      > Use a comparitor with the '-' input feed by a 10K potentiometer wiper
      >
      > and a 4.7K resistor on each end (to VCC and GND).
      >
      > Take the output of the 555 timer capacitor terminal and connect it to
      >
      > the '+' terminal of the comparitor.
      >
      > Take the output of the comparitor and use it to drive the SSR-240D25
      > (+ terminal to VCC, -terminal to the comparitor output). I recommend
      > running the 555 and comparitor circuits on about 12V.
      >
      > You now have a burst fire controller with zero cross (minimal noise
      > generation). The comparitor will turn on when the setting sees the
      > ramp capacitor voltage above the potentiometer setting. The cap
      > voltage varies from 1/3 to 2/3VCC. The two resistors allow you to use
      >
      > more of the ajustment range that if you simply attached the pot to
      > VCC and GND without them.
      >
      > MOUSER has them (SSR-240D25) at a slightly lower price.
      >
      > Sven
      > --- In Distillers@yahoogroups.com, "Robert Hubble" <zymurgybob@...>
      > wrote:
      > >
      > > Harry,
      > >
      > > Thank you and all the others for answering my 50-year-old question
      > about the
      > > bi-metal infinite switch. Although I currently use propane to power
      >
      > a
      > > potstill, I am looking at building a continuous-run reflux still
      > after the
      > > one on Tony's site, so I MAY be in the market for building a good
      > power
      > > controller.
      > >
      > > I have looked at the 555 or counter controlled SSR as mental
      > exercises
      > > (while making long drives) for a long time, but I think push is
      > coming to
      > > shove pretty soon now. I'm a long-time user of the Howard W. Sams
      > > literature, from the Sam's Fotofact "How to repair your electronic
      > whatever"
      > > of the 1950's to the later cookbooks they do so well. I even
      > worked with a
      > > woman who wrote one of the Sam's how to UNIX books. After reading
      > this, I
      > > went straight to the cookbook section of my electronics library,
      > and the 555
      > > cookbook was gone, loaned out, I guess, or maybe in a project box
      > in the
      > > garage.
      > >
      > > Anyway, all this drove me to make a parts search for the solid-
      > state-relay,
      > > and Digikey is my search-engine of choice. The Potter-Brumfield
      > SSR-240D25,
      > > at $38.62 US, is opto-coupled, zero-crossing, 280V and 25A relay.
      > For those
      > > who do not know, ordering almost anything through Digikey
      > (www.digikey.com)
      > > is pretty easy.
      > >
      > > Thanks for the answer, and thanks for getting me thinking about the
      >
      > > vodka-fuel still again.
      > >
      > > Zymurgy Bob, a simple potstiller
      > >
      > ...snip...
      >
      >
      >
      >


      Cheers,
      Rob.

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