Sunday, March 31, 2013

How to Make a Simple Active Low Pass Filter Circuit Using IC 741

In electronics, filter circuits are basically employed for restricting the passage of a certain frequency range while allowing some other band of frequency into the further stages of the circuit.

Primarily there are three types of frequency filters that are used for the above mentioned operations.

These are: Low pass filter, high pass filter and the band pass filter.
 As the name suggests, a low pass filter circuit will allow all frequencies below a certain set frequency range.
A high pass filter circuit will allow only the frequencies which are higher than the preferred set range of frequency while a band pass filter will allow only an intermediate band of frequencies to flow to the next stage, inhibiting all frequencies which may be outside this set range of oscillations.

Filters are generally made with two types of configurations, the active type and the passive type.
Passive type filter are less efficient and involve complicated inductor and capacitor networks, making the unit bulky and undesirable. However these will not require any power requirement for itself to operate, a benefit too small to be considered really useful.
Contrary to this active type of filters are very efficient, can be optimized to the point and are less complicated in terms of component count and calculations.

In this article we are discussing a very simple circuit of a low pass filter, which was requested by one of our avid readers Mr.Bourgeoisie.

Looking at the circuit diagram we can see a very easy configuration consisting of a single opamp as the main active component.
The resistors and the capacitors are discretely dimensioned for a 50 Hz cut OFF, meaning no frequency above 50 Hz will be allowed to pass through the circuit into the output.
For technical explanation of the circuit you may refer to the data provided here.