Want to know about passive filter circuits, active filter circuits and electronic low-pass filters? We will discuss these three one by one in this article.
We have discussed low-pass filtering before. In this article, we will discuss passive filter circuits, active filter circuits, and electronic low-pass filters."
Passive filter circuit
The passive filter circuit has a simple structure and is easy to design.
But its passband amplification and its cutoff frequency vary with load.
Therefore, it is not suitable for occasions with high signal processing requirements. Engineers typically use passive filter circuits in power circuits, like filtering after rectifying DC power supplies. Or use LC circuit filtering when using large current loads.
Active filter circuit
The load of the active filter circuit does not affect the filter characteristics.
Therefore, people often use it in situations with high signal processing requirements.
RC networks and integrated operational amplifiers generally make up the components.
You must use it with a suitable DC power supply and you can also amplify it.
However, the composition and design of the circuit are also more complex.
They are not suitable for high voltage and high current situations, but are only suitable for signal processing.

The voltage amplification of a filter can help identify its type by examining its amplitude-frequency characteristics.
This can show if the circuit is a low-pass, high-pass, band-pass, or band-stop filter. The voltage amplification helps in accurately describing the filter's behavior. If you can analyze the frequency bands of the passband and stopband, you can determine the type of filter.
A low-pass filter exhibits a decrease in its voltage amplification factor as the signal frequency increases towards infinity. The voltage amplification factor increases as the signal frequency approaches zero.
A high-pass filter amplifies high signal frequencies and reduces low signal frequencies. This means that the voltage amplification factor is high for high frequencies and low for low frequencies. In other words, the filter allows high frequencies to pass through while blocking low frequencies.
A band-pass filter amplifies voltage less as the signal frequency gets closer to zero or infinity.
A band-stop filter has a constant voltage amplification factor as the signal frequency approaches zero and infinity. However, the voltage amplification factor decreases within a specific frequency range.
Electronic low pass filter
Many, many different types of filter circuits with different frequency responses exist.
The meaning of 'low' and 'high' - such as cutoff frequency - depends on the characteristics of the filter.
Engineers can design electronic filters for any desired frequency range, including microwave frequencies and beyond.
The above is an introduction to passive filter circuits, active filter circuits and electronic low-pass filters.