Dear RDHeiliger
I had to comment because I personally feel you "hit the button" so to say with your commnts, particularly with the last sentence, where I feel if DC is used (or the heater supply is converted to DC if AC), one could build a very cheap Pulse With Modulator from say a 555 chip and a handfull of other compnents.....and once the trimmer has been set, there will probably be little need to change its setting.....of course if one had a thermometer that can read to say 200°C as a seperate unit, one could check out the temperature....
There are some very cheap Non contact Laser versions that can read to almost 400°C for very little money on ebay for example, look here:-
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=250528259516 For less than $16.........thats cheap!!!
regards
Andy
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When I looked into using thermistors for laminator temp control, I looked at the maximum temperature spec of the thermistor. Few of them can withstand 170 ∗C. The glass bead type seem to be the only thermistors capable of going that high. They then get expensive and hard to find. Believe that is why Steven suggested pulling one out of an old laser printer fuser unit. Also, one needs to calibrate and linearize the thermistor output. Meaning, one needs to have some other accurate instrument to develop a lookup table. The same goes for using a thermocouple and an opamp. I personally decided that $30 for the AD595 and a thermocouple was worth not hassling with other methods.
One could always just buy a rheostat and keep turning up the heat until one gets a good transfer and not worry about the actual temperature. Since a good transfer is the desired end result. Perhaps we some times over engineer things????????????
RD
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