2.3 Passive filters and resonance

Outcome 3 of 6 in domain 2 · Alternating current and signals

Low-pass, high-pass, LC.

My targets

I declare:

Size an RC low-pass for a given cutoff frequency, build it and plot its response at three frequencies.
Explain the slope of a first-order filter (−20 dB per decade) and what a second stage adds.
Calculate the resonant frequency of an LC and observe it on the oscilloscope.
Smooth a microcontroller’s PWM output into an adjustable DC voltage, and measure the residual ripple.
Build a band-pass, measure its width, and express gains and losses in decibels.
Diagnosis: a circuit that whistles or oscillates unintentionally, find the parasitic LC or the resonating loop.