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Re: Triac circuit

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  • David Pickles
    Hi All, When I was using the heater control for heating my Hydroponic nutrients,I chose 3.3mf for the timing capacitor Ct. The reason being, it looked good, as
    Message 1 of 1 , Apr 23, 2000
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      Hi All, When I was using the heater control for heating my Hydroponic nutrients,I chose 3.3mf for the timing capacitor Ct. The reason being, it looked good, as I had a neon indicator strapped across the power out socket & it would flash on and off slowly indicating the unit was working--------purely cosmetic. No good for the still tho for the reason you stated, the reading on the column thermometer was going up & down like a yoyo! However, to overcome this, just increase the value of Ct to 100mf
      The beauty of such a device is, since it has a sensing resistor (Rntc) this resistor can be strapped to the outside of the boiling chamber & the control set to produce a rolling boil,further to this, a 2500 watt element can now be used as it will climb in temperature rapidly until the required rolling boil is reached, set by the potentiometer Pr.
      I have been reluctant to pass over such information re heater controllers ,thinking it might be irresponsible of me as there are great danger potential if wired incorrectly! I think any such device should be built by an Electronics Technician, as if the Live & Neutral are transposed & the Rntc resistor is not sufficiently electrically insulated, the still will become LIVE! It is for this reason I will suggest that EVERYBODY uses one of those earth leakage detectors which can be bought from any Hardware store or Electrical store. I use one all the time, we all know that electricity & water do not mix  so buy one NOW!!!
      If you want to make it even simpler, go to the Philip's sight again & type in TDA1024 then download the applications data. This is a similar device but without the sensing temp resistor. These units should be built in a diecast box then one can use the case as a heat sink for the Triac---if you don't the triac will suffer thermal runaway & latch full on. Both these devices have zero switching--so no radio interference.
      Best of luck.
      Now its question time:-
      What temperature do I set the wash at whilst distilling---78C?----99C? or somewhere in between
      Regards,
      Dave Pickles.
      Email :   david-pickles@...
      ----- Original Message -----
      Sent: Wednesday, 19 April 2000 07:45
      Subject: Re: Triac circuit

      Thanks David,
       
      A nice little chip.  Only snag is the burst fire repetition time - quoted typical value on page 2 is 31 seconds.  This is fine for a room heater, but would give surge boiling in the application that we want.  The >30 sec bit is obviously built in to satisfy European regulations on repetition rate for switching of heavy loads.  However, I believe that I've overcome that little snag with my circuit, which will be tested tonight (I had some rewiring to be done to improve layout neatness).  Details will be forwarded to you as soon as I'm satisfied it's working safely and correctly.  Should be in a day or two if I haven't fried myself before that.
       
      TTFN
      Mike
      -----Original Message-----
      From: DAVID REID <nzag@...>
      To: Mike <mike@...>
      Cc: DAVID REID <nzag@...>
      Date: Tuesday, April 18, 2000 10:14 PM
      Subject: Triac circuit

      Mike,
              Dave Pickles sent me the following url for the Phillips Triac Circuit which he may have sent to you as well.
      B.r., David 
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