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
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
----- Original Message -----
Sent: Wednesday, 19 April 2000
Subject: Re: Triac circuit
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.
DAVID REID <nzag@...>
DAVID REID <nzag@...>
Tuesday, April 18, 2000 10:14 PM
sent me the following url for the Phillips Triac Circuit which he may have
sent to you as well.