hi all
this isnt realy a homework ques. but im trying to undersatnd how this circuit works so i figured this is the best place for this post.
i built myself a heart rate monitor that i found **broken link removed**
i had to add a bandpass filter to get the results that they got on the website
but it works fine.
The Question:
i dont understand what C1 is doing for the circuit and why the circuit doesnt work without it. and why i cant take C1 and R2 out of the circuit in which case the changing resistance of the LDR(R3) would change the potential at the positive input of the opamp thus giving me a pulse for each heart beat?
i hope my ques. was clear any help will be greatly appreciated
thanx in advance,
yusim
this isnt realy a homework ques. but im trying to undersatnd how this circuit works so i figured this is the best place for this post.
i built myself a heart rate monitor that i found **broken link removed**
i had to add a bandpass filter to get the results that they got on the website
but it works fine.
The Question:
i dont understand what C1 is doing for the circuit and why the circuit doesnt work without it. and why i cant take C1 and R2 out of the circuit in which case the changing resistance of the LDR(R3) would change the potential at the positive input of the opamp thus giving me a pulse for each heart beat?
i hope my ques. was clear any help will be greatly appreciated
thanx in advance,
yusim