What purpose unity gain buffer amplifiers serve

[retupmoc]

urgent help needed

Can anyone tell me what purpose unity gain buffer amplifiers serve and why do you connect 2 low pass filters of same corner frequency by cascading them using one of these op amp buffers and not directly together. Also can you show me the diagram of this and where the feedbacks taken from. I am totally confused. Any help would be much appreciated

 

[dlgoff]

Unity gain amplifers or voltage followers are used to buffer. i.e. they can be used to interconnect two parts of a circuit to keep the parts from interacting with each other.

They have a high input resistance and a low output resistance.

Regards

 

[ravenprp]

Unity gain buffer amplifiers serve the purpose of providing a high input impedance and low output impedance to a circuit. This means that they can take in a weak signal and amplify it without altering the signal's characteristics. They also help to isolate the input and output signals, preventing any changes in the input signal from affecting the output signal.

In the case of connecting two low pass filters of the same corner frequency, cascading them using a unity gain buffer amplifier ensures that the filters are working independently and do not interfere with each other. This is because the buffer amplifier provides a high input impedance, preventing any loading effects on the filters.

The diagram for cascading two low pass filters using a unity gain buffer amplifier would look like this:

[Input Signal] -> [Low Pass Filter 1] -> [Unity Gain Buffer Amplifier] -> [Low Pass Filter 2] -> [Output Signal]

The feedback for the buffer amplifier is taken from the output of the amplifier and connected to its inverting input. This creates a negative feedback loop, stabilizing the amplifier's gain and ensuring that the output signal is an exact replica of the input signal.

I hope this helps to clarify the purpose of unity gain buffer amplifiers and how they are used in cascading filters. If you need further assistance, please don't hesitate to ask.