An Audio Amplifier Using LM386 Op-Amp IC

The primary objective of this project is to design a audio amplifier circuit using the
LM386N Operational Amplifier (Op-Amp). This versatile and widely used IC is known for
its simplicity and effectiveness in audio applications.

Input Configuration: Two resistors are strategically employed. Each stereo channel
is connected to one resistor, and the junction of these resistors serves as the mono
input to the LM386N Op-Amp. This simple resistor network combines the left and
right audio signals, resulting in a mono audio output.
Coupling Capacitors: To facilitate DC isolation and allow only the AC audio signal
to pass through, 100 microfarad capacitors are coupled to pins 6 and 7 of the
LM386N Op-Amp. These capacitors ensure that any DC bias in the input signal is
blocked, preventing potential damage to the amplifier and improving overall
performance.
Filtering Capacitors: In order to enhance audio signal quality and eliminate highfrequency distortion, two capacitors are strategically placed. A 1000 microfarad
capacitor is positioned between the output of the LM386N Op-Amp and the speaker.
This capacitor acts as a low-pass filter, attenuating high-frequency components and
allowing only the audio signal to reach the speaker.
Additionally, a 100-microfarad capacitor is connected from the output to the ground.
This capacitor serves as a decoupling capacitor, filtering out any residual highfrequency noise or distortion before the signal is delivered to the load.
Overall Functionality: The LM386N Op-Amp, configured in a non-inverting
amplifier mode, amplifies the mono audio signal, providing sufficient gain to drive the
connected speaker. The combination of input resistors and coupling and filtering
capacitors ensures that the amplified audio signal is mono, free from DC bias, and
devoid of unwanted high-frequency artifacts.
In summary, this project capitalizes on the LM386N Op-Amp's capabilities to create
a simple yet effective stereo to mono audio amplifier, demonstrating the integration
of resistors and capacitors to shape the input, enhance signal quality, and deliver a
clean and amplified audio output.