Low Voltage Signal to current signal Conversion

Discussion in 'General Electronics Chat' started by sdutta2, Mar 21, 2011.

  1. sdutta2

    Thread Starter New Member

    Mar 21, 2011
    1
    0
    Hii I have a low voltage signal arounf 0.1 to 2.0 mv I want to convert it to a current signal in the order of several mili-amps so that it is less influenced by noise in the circuit. Are there standard Op-Amps that can do this stuff ? The voltage source has almost zero driving capability. It is an output of a thermo-coupler. Let me know guys if you have any idea as to how to implement it.
     
  2. russ_hensel

    Well-Known Member

    Jan 11, 2009
    818
    47
    Are there standard Op-Amps that can do this stuff ? Yes. Look for one with low and stable offset voltage. This is pretty low voltage for a thermocouple, the temp. must be low too. There may be better temp. sensors for your ( unknown ) application.
     
  3. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    How about going digital?

    http://www.sparkfun.com/datasheets/IC/MAX6675.pdf

    If you must stay analog, here's some good stuff on I/E converters:

    http://www.allaboutcircuits.com/worksheets/opamp7.html

    Here's a T/C amplifier for J, K, (and maybe T) T/C's:

    http://www.analog.com/static/imported-files/data_sheets/AD594_595.pdf

    You can get quite a bit of gain from it so it should be pretty easy to feed into an E/I.

    There are commercial T/C transmitters that provide a 4-20 ma output for whatever T/C you have, here's one:

    http://www.newportus.com/ppt/TX93A_TX94A.html
     
    Last edited: Mar 21, 2011
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