Circuit Theory-2 #21 | Low-Pass and High-Pass Filters

Instructor: Dr. Süleyman Burak ÇELİK

In this Circuit Theory-2 lesson we turn frequency response into two practical RC filter circuits: the low-pass filter and the high-pass filter. You will learn: - What pass band, stop band, and cutoff frequency mean - Why the cutoff of a first-order passive filter is the -3.01 dB point - How the RC low-pass works when the output is taken across the capacitor - How the RC high-pass works when the output is taken across the resistor - Why both circuits share tau = RC, omega_c = 1/RC, and f_c = 1/(2 pi RC) - How low-pass and high-pass magnitude curves compare on a Bode plot - How their phase curves become symmetric around the corner frequency - How to design a simple RC filter from a target cutoff frequency - Common traps: output node choice, Hz vs rad/s, gradual rolloff, and loading effects Timestamps: 00:00 Low-pass and high-pass filters 00:03 From frequency response to filter circuits 00:31 Filters select frequency bands 00:51 RC low-pass 01:24 RC high-pass 01:54 Same corner frequency 02:26 Bode magnitude comparison 02:51 Phase comparison 03:17 Design example 03:47 Common traps 04:17 Wrap Next lesson: band-pass behavior, resonance, and Q. Part of the Circuit Theory-2 playlist by AcEdumy.