1. Introduction
This article mainly introduces how to understand the principle of the filter to separate different frequency signals for reference.
Two, basic terms
Filter cutoff frequency:
Gain:
Impedance and Capacitance:
The calculation method of capacitive reactance:
the unit is also ohm:
Third, the principle of series voltage division
Calculate the capacitive reactance voltage and divide the voltage to get the relationship between output and input:
When the frequency is infinite, the capacitive reactance is 0 ohms, and the input and output can be obtained according to the divided voltage.
High pass filter and low pass filter:
Three, summary
This article mainly briefly introduces the principle of the filter, and the high-pass and low-pass filters for reference. Welcome to discuss and exchange~