thermocouple interfacing

Discussion in 'The Projects Forum' started by getaneh, May 28, 2015.

  1. getaneh

    Thread Starter New Member

    May 28, 2015
    I am doing a project,and I want to interface a thermocouple with an ADC terminal of an LPC 2138 microcontroller ,I am using 2M K type thermocouple with a temperature range of 0-800 centigrade,,,so do I need any ampifier ,or how can solve it
  2. MrAl

    Distinguished Member

    Jun 17, 2014

    Yes you need an amplifier because the output at low temperatures is very low.
    You should read up on this on the Analog Devices web site i think to get a feel for what is involved. You not only need an amplifier you need to arrange the two wires correctly so that you get the right readings. For example, you need what is called 'cold junction' compensation and there are various ways of dealing with this, and i think the AD site has some good information on this, and they make a product that interfaces to K type probes with more ease.
    ebeowulf17 likes this.
  3. DickCappels


    Aug 21, 2008
    ebeowulf17 likes this.
  4. ebeowulf17

    Well-Known Member

    Aug 12, 2014
    I agree with the responses above that you should read up some to better understand thermocouples.

    I've used the Analog Devices AD8495 and AD595 in several projects and been thrilled with the performance and convenience of these circuits, and found the documentation extremely helpful. Might be worth checking out. Also, if this is a handmade project and you don't want to work with SMT components, Adafruit makes a handy breakout board for the 8495.