Electronics Fundamentals/Electronic Filter/Low Pass Filter

RC Low Pass Filter

Configuration

Characteristics

${\frac {V_{o}}{V_{i}}}={\frac {\frac {1}{j\omega C}}{R+{\frac {1}{j\omega C}}}}={\frac {1}{1+j\omega T}}$

$T=RC$

$\omega _{o}={\frac {1}{T}}={\frac {1}{RC}}$

LR Low Pass Filter

Characteristics

${\frac {V_{o}}{V_{i}}}={\frac {R}{R+j\omega L}}={\frac {1}{1+j\omega T}}$

$T=RC$

$\omega _{o}={\frac {1}{T}}={\frac {1}{RC}}$

Summary

Low Pass Filter has a stable voltage which does not change with frequency over a low range of frequency . Low Pass Filter can be constructed from RC, LR