This document discusses capacitive reactance and how it varies with frequency. It explains that capacitive reactance decreases as frequency increases, so all the voltage passes through the capacitor at high frequencies rather than low frequencies. This concept is key to understanding how low-pass and high-pass filters work by allowing either low or high frequencies to pass through based on the capacitive reactance.

1. Basics Circuits by Thomas L floyd PG 835

3. Output is taken across the capacitor.

4. We know
When input is 0Hz(DC)
is gradually decreases as frequency increases. All the voltage goes through
capacitor.
Critical frequency
Xc =
1
2πfcC
Why capacitive reactance is less at high frequency? This concept is essential in-
order for understanding Low pass and high pass filter.
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Xc = ∞
Vout
fc = R