On Wed, 18 Apr 2001, Allen Dick wrote:

> > Also use a temperature controller instead of a thermostat. They are
> > accurate to less than 1 degree...
>
> What exactly are temperature controllers, and where do you buy them?

They are an electronic thermostat. The sensitivity can be made very small,
but as you know the circulation of air in the chamber is probably more
important than the sensitivity of the thermostat. They are readily
available in Edmonton at stores specializing in temperature control
equipment for industry. The industrial ones go for about $100-$200, and
have adjustable set points, different voltage for driving the relays that
actually turn the equipment on and off, annunciator outputs for out of
range conditions etc.  You can build a very good one for your own special
purposes for about $20 not including the relay.


                                                Best regards

                                                Donald Aitken