Electronic – Capacitors and filtering


I noticed that in many audio op-amps, RC constant is designed so that the cutoff frequency is about 16 Hz. I think that's because the human ear responses to frequencies higher than 22 Hz. But I am a bit confused. If the RC component decides the cutoff frequency, why do they always use values of about 100kOhm and 0.1uF? Can't it also be a different combination, such as 1kOhm and 10 uF. Is that because the current issue?

Best Answer

1) the reason there is a 16KHz cut off: While our ears do have a hearing range of 20-22KHz the actual range that we use in our every day life for hearing is about 6-10KHz (at most)

If you are listening to music, one of the things to realize is that pitches, musical notes use a logarithmic scale. so A4 is at 440Hz while A5 880 Hz A6 is at 1760 Hz what this means that there are only a few notes are left to be able to play above 16kHz. Just for reference, the highest note played on a piano would be 7.9kHz which is a B


2) 100K ohm resistors are cheap and common, same-thing with the capacitor. its the most cost effective choice.