Question

Design an RC and RL Low Pass Filter with a 3 dB point of 30kHz. What is the rate of roll off after the 3 dB point (per Decade and per Octave)?

Answer 1

An RC low pass filter has a rate of roll-off of -20 dB per decade or -6 dB per octave, while an RL low pass filter has the same rate of roll-off.

Step-by-step explanation:

An RC (resistor-capacitor) low pass filter is designed using a resistor (R) and a capacitor (C), while an RL (resistor-inductor) low pass filter is designed using a resistor (R) and an inductor (L). To design an RC or RL low pass filter with a -3 dB point of 30 kHz, we first need to calculate the values of the resistor (R) and the capacitor (C) or inductor (L) that are required.

The rate of roll-off after the -3 dB point is an indicator of how quickly the filter attenuates the frequencies above the -3 dB point. The rate of roll-off is measured in dB per decade or dB per octave. In an RC low pass filter, the rate of roll-off is -20 dB per decade or -6 dB per octave. In an RL low pass filter, the rate of roll-off is -20 dB per decade or -6 dB per octave.