Rc Time Constant

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Rc Time Constant

The time constant

au

is related the Cutoff Frequency ''f''_c, an alternative parameter of the RC circuit, by
:

au = R \cdot C = rac{1}{2 \pi \cdot f_c}

.
or, equivalently,
:

f_c = rac{1}{2 \pi \cdot R C} = rac{1}{2 \pi \cdot 	au}

,

Short conditional equations:
:(''f''_c in Hz) = 159155 / (τ in µs)
:(τ in µs) = 159155 / (''f''_c in Hz)

Other useful equations are:
:rise time (20% to 80%)

t_r \approx 1.4 	au

:rise time (10% to 90%)

t_r \approx 2.2 	au

Standard time constants and cutoff frequencies

for pre-emphasis/de-emphasis RC filters:

SEE ALSO

Time Constant and Exponential Decay

RC Circuit and RL Circuit

Filter (signal Processing) and Transfer Function

Cutoff Frequency and Frequency Response

Emphasis , Preemphasis , Deemphasis

High-pass Filter , Low-pass Filter , Band-pass Filter

EXTERNAL LINKS

Conversion time constant $au$ to cutoff frequency f_c and back

RC time constant