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High Pass Filter Circuit


Himanshu Choudhary

A high pass filter is just opposite to a low pass filter. It is employed to avoid or retain frequencies which are lower than filter’s cutoff frequency. It is also known as low-cut filter since it provides a difficult passage to low frequency signals from source to output. High pass filters find their applications in multimedia circuits such as audio tweekers etc. Also, the concept of high pass filtering is used in digital signal processing of images and animated data.

It is, however, pretty interesting to know that a low pass filter can be converted to high pass and vice versa just by shuffling the combination of resistance and capacitance. 

Let's make an interesting project using high pass filter circuit




This high pass filter circuit project filters a frequency spectrum or any mix of frequencies. The frequencies below the cut-off frequency of the filter are blocked effectively by the capacitor C. This circuit has a resistor connected in parallel and a capacitor in series with the output. The principle involved : the reactance of the capacitor is inversely proportional to the frequency applied, i.e., Xc =  1/WC. The voltage across the capacitor C goes on increasing with the decrease in frequency. Thus the frequencies below the cut off frequency are effectively reduced in amplitude. The cutoff frequency is the design parameter of the filter and depends on the value of capacitor C and resistor R according to the relation  f = 1/2RC.


Circuit Diagram


Resistor Image

Resistor is a passive component used to control current in a circuit. Its resistance is given by the ratio of voltage applied across its terminals to the current passing through it. Thus a particular value of resistor, for fixed voltage, limits the current through it. They are omnipresent in electronic circuits.

Capacitor image



Capacitor is a passive component used to store charge. The charge (q) stored in a capacitor is the product of its capacitance (C) value and the voltage (V) applied to it. Capacitors offer infinite reactance to zero frequency so they are used for blocking DC components or bypassing the AC signals. The capacitor undergoes through a recursive cycl...

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