Jul 26, 2007 #1 X xiexi Member level 4 Joined Jan 14, 2005 Messages 79 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,286 Activity points 613 I just want 4kHz LPF, I design R=780K, C=10pF, and 3 same RC in series, the -3dB is about 4KHz, is the design right? if right but the size is too big to integrate in IC, can anyone give me some instruction, thanks!
I just want 4kHz LPF, I design R=780K, C=10pF, and 3 same RC in series, the -3dB is about 4KHz, is the design right? if right but the size is too big to integrate in IC, can anyone give me some instruction, thanks!
Jul 31, 2007 #2 N neter Member level 2 Joined Jul 15, 2004 Messages 46 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,286 Activity points 341 because -3dB=4KHz request, so fc1=fc2=fc3=4kHz, fc=1/2pi*R*C (if you use passive RC filter)