I have to design a low pass filter to put at the end of a thermocouple. The Thermocouple has a 30.8mohm impedance. I am going to have a signal with noise at high frequencies. This AC signal has an amplitude around 15V (it is a really noisy signal) and I am interested in an output signal not more than 10Hz. Is one stage adequate ? Should I consider a multi stage RC filter? There are many combinations of R and C for setting a cut off frequency of 100Hz. What should I consider when choosing R and C?. I am going to measure the output of the combination thermocouple+RC filter with this passive probe: http://tmi.yokogawa.com/es/products/oscilloscopes/voltage-probes/701938-200-mhz-passive-probe/
I have been thinking about R=100ohm and C=15uF, R=1kohm and C=1.5uF... but I am not sure if I am not considering something important.