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20Hz to 200Hz Variable High-Pass Filter
The circuit was designed to create a high-pass filter that can be variably change to work with frequency range from 20 Hz to 200 Hz.
- High Pass Filter – an electronic circuit that allows the passage of high frequencies while opposing any unwanted low frequency components
- TL072 – a low noise JFET input operational amplifier with features such as common-mode input voltage range, high slew rate, operation without latch up, compensated internal frequency, high input impedance at the JFET input stage, low noise, low total harmonic distortion, protected from output short circuit, low input bias and offset currents, wide common-mode and differential voltage ranges, and low power consumption
The operation of the high-pass filter in a stereo system is represented by the functionality of a tweeter where a capacitor is connected in series as it provides the treble audio to the speaker. It has a rated cutoff frequency that is above which the output voltage increases above 70.7% of the input voltage.
A high-pass filter circuit is typically constructed using the series combination of a capacitor and a resistor known as RC circuit. It can also be constructed using inductors and capacitors that are arranged in either a T or a pi network.
This variable high-pass filter circuit is also known as low-cut filter operates in the frequency range of 20 Hz to 200 Hz which covers a part of the extremely low frequency (ELF) and a part of super low frequency (SLF). It can be used to provide more details of sound signals. The two 47K ohms potentiometers are used to regulate the frequency response as it is produced in the two extreme points.
In general, high-pass filters can be used as part of an audio crossover guide the high frequencies to a tweeter while preventing the passage and interference of bass signals which could damage the speaker. Other types of high-pass filters like the rumble filters are used in tape decks and record players to remove the unwanted sounds near or below the lower end of the audible range like the noises coming from motors or footsteps. In the amplifier input and output, high-pass filters are also used for AC coupling.