I wish to amplify the signal of thermocouple 5000 times. Which instrumentation amplified is better?
AD8421 or AD8221... OR OTHER
You should consider that there a pump motor 1/4HP near of the circuit.
Please refer to this thread https://ez.analog.com/amplifiers/f/q-a/536158/rfi-filter-ad8221-y-amplification-stage-to-thermocouple as you have similar issue and it already have a discussion regarding the topic.
Feel free to reply to that thread or let me know if you have different concerns.
Thank you and keep safe.