camperhead
New Member
I wanting to put together a temp controlled switch using a k type thermocouple to simply turn a relay on and off with the set temp is reached. Any help or suggestions would be great
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RadioRon said:As it is our nature to try and understand the greater context, I wonder:
However, to answer your question as originally asked, start with an accurate thermocouple interface:
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https://www.sparkfun.com/commerce/product_info.php?products_id=306
then wire the output of this to a comparator circuit
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and use a potentiometer in the second input of the comparator to set your desired switching point. Then use the output voltage of the comparator to drive a relay:
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I wonder why some of you cant give the OP the credit for having a little bit of common sense. He obviously wants to control an oven at some high temperature, the K type is good to over 2000°F and its accuracy is more than adequate, in most instances. Substituting a thermistor or semiconductor is NOT an option at those temps.RadioRon said:As it is our nature to try and understand the greater context, I wonder:
- why use a K type thermocouple rather than a thermistor or semiconductor temperature sensor? The thermocouple requires a bit more interface circuitry and so is not the most convenient choice. A K type is not the most accurate choice either so the alternatives, which are not particularly accurate either may be considerably more convenient.
- while a relay is easy to use, it is also slow, noisy, less power-efficient, larger and perhaps even costlier than a semiconductor solution so, why use a relay?
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