I would like to measure temperature with a very high acquisition rate during a test that takes place in under 1ms. I was thinking of using a thermocouple and an oscilloscope. Which kind of signal conditioning device or circuit would I need? Would the thermocouple actually be able to sense rapid changes in temperature? or a different sensor would be needed?
Dear Gustavo,
The thermocouple can have very small thermal capacity. So, it can used to acquire rapidly changing object temperature.
You need to use with it a suitable national DAQ card, The data acquisition card can be directly connected to the thermocouple in one side and to the oscilloscope or even a computer on the other side.
When using oscilloscope you can even reduce the conditioning circuit to a suitable operational amplifier that just amplify the signal to monitor it by the oscilloscope.
Best wishes
The needed data acquisition rate is >1000 samples/sec which is possible with modern multimeters (DMM) with IEEE-488 computer interface. The measurement can be started near the test time which lasts for 1 ms or so. The input voltage to the DMM can be adjusted by maintaining the reference junction at a given temperature.
Thermocouple sensors have fast thermal response time as the mass of the junction is low.
I would look at some thermocouple amplifier like
Digi-Key Part Number 1528-1407-ND
https://www.digikey.ie/products/en?keywords=1528-1407-ND%20
The response time is defined by thermal coupling to the object and the mass o the thermocouple. Some special 'fast' thermocouples exist, e.g.
https://www.thermoworks.com/IT-23
Dear Gustavo,
The thermocouple can have very small thermal capacity. So, it can used to acquire rapidly changing object temperature.
You need to use with it a suitable national DAQ card, The data acquisition card can be directly connected to the thermocouple in one side and to the oscilloscope or even a computer on the other side.
When using oscilloscope you can even reduce the conditioning circuit to a suitable operational amplifier that just amplify the signal to monitor it by the oscilloscope.
Best wishes
Please read my book
The American University Laboratories For Electrical Engineering Part 2
Part of my book is measurement.
enjoy.
You can connect thermocouples with proper signal conditioning units having cold junction compensation (one may use isothermal box) and amplification circuitry and then output terminals may be connected with oscilloscope. Signal conditioning will depend on which type of thermocouples you are using.
For rapid change of temperature, thermistors are suitable. But range matters.
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