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

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  • Sven Pfitt
    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
    Message 1 of 29 , Apr 3, 2006
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      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...
    • 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 2 of 29 , Apr 3, 2006
      • 0 Attachment
        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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