Hi everyone,

In the sound detector circuit we use Microphone to convert the audio signal to electrical signal and then pass it through a high pass filter to remove dc offset
but i can use only capacitor to do this job ! why we need a resistor in parallel with it ?

thanks

 

Post the schematic

If you just use a capacitor then you are just coupling the signal to remove DC offset , If you are using a cap in series and resistor in parallel then it's going to become a high-pass filter (I think)