what is the best combination of a resistor and a capacitor for making filters in wearable electronic circuits?
What is generating the signal you want to filter?the first combination is R=47k, C=68nF
The second Combination is R=680 and, C=4.7uF
Which one is best to filter 50Hz and why?
As you are no doubt aware the solutions are NOT unique. You cannot determine two component values from a single equation. Also you cannot determine an optimal (best) value without specifying something to optimize. The answer to your question is indeterminate.the first combination is R=47k, C=68nF
The second Combination is R=680 and, C=4.7uF
Which one is best to filter 50Hz and why?
Your resistances and capacitances were orders of numbers wrong. I corrected them.
Here is an extremely simple 50Hz passive notch filter:
Pay attention to the source and load impedances.There are unlimited combinations of resistors and capacitors to filter a specific frequency in the circuit. For example, I am filtering 50Hz from the circuit. There are a lot of combinations of resistors and capacitors to filter out that frequency. If, I make two different circuits of 50hz filter with different combinations of resistors and capacitors. Theoretically, both circuits will remove 50hz frequency from the circuit. Practically, Is there any other effect on the circuit?