Problem definition
In this project.Since the LED is DC component and the input signal is AC typed, a third operation must be added to convert the AC signal to DC signal.We are working on designing and implementing the circuit which can be used to detect the whitling sounds and provide a proper indicator according to the intensity and the frequency of the detected sound.this operational amplifier is using to magnify the amplitude of the signal to make it able to activate the output component.The circuit is based on the microphone as input component and the proper visual output component such as the LED.This operation can be applied to remove the unwanted part from the input signal.