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Circuit Design for microvolt range signal

Circuit Design for microvolt range signal

Circuit Design for microvolt range signal

(OP)
The problem is this : I am looking for low cost circuit design to detect microvolt signal in the range of 0 to 500 microvolt with aaccuracy of 2 microvolt from a set of thermocouples.

   I have looked at two designs. First a circuit with an analog filter and 24-bit A/D with a Sigma-Delta filter ( and a low-cost microprocessor) and amplifier. This design is costly due to the high cost of this kind of A/D.

    Second design uses a low-cost microcontroller with 10-bit A/D and amplifiers. The amplifiers give noise that is bigger than the signal. The microcontroller does not allow the use of analog filter

RE: Circuit Design for microvolt range signal

Suggestion: Visit
http://www.thomasregister.com
and type Amplifiers: Electronic under Product / Service
that will return 31 companies to inquire about accurate electronic amplifiers

RE: Circuit Design for microvolt range signal

Max... the ckt you are looking for needs several things... good noise reduction (common mode noise), very good DC specs, and some gain to get the signal "up there" for your A/D to work with... all these things can be found in an "instrumentation amp" or IA...

Look to Burr-Brown (now a div. of Texas Instruments), or AD (Analog Devices), or Linear Technologies for stock IA's. All three have web sites. You will want a slow one (under 3Mhz GBW product) that has bipolar inputs (not FET). In the device data sheets you will find recommended ckts for using as a thermocouple amp. Look into also providing a "cold junction" to compensate ambient.

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