In this project, we will show you how to build LM386 Audio Amplifier Circuit. It is a very low cost audio amplifier and can power any speaker. For the cost and size of the circuit, the sound from the LM386 Audio Amplifier can be adequately loud.
There are many Audio Amplifier Circuits designed using LM386 IC. The main problem with these circuits is noise and interference. The noise from the Amplifier Circuit designed in this project is considerably less and if designed on a proper circuit board, this will make a great Audio Amplifier.
The Audio Amplifier using LM386 is a low power circuit that can deliver a maximum power of 1 Watt (1W) and can be used in a wide range of applications like portable speakers, laptop speakers, etc.
· LM386 Audio Amplifier IC
· 1000 µF Capacitor
· 100 µF Capacitor
· 10 µF Capacitor
· 0.047µF (470)Capacitor
· 10 KΩ Potentiometer
· 10 Ω Resistor (1/4 Watt)
· 4 Ω Speaker
· 12V Power Supply
· Connecting Wires
· stereo to mono converter adaptor (for stereo output device)
Introduction to LM386
The LM386 is an all – in – one Class AB Audio Amplifier IC that can be used in a variety of applications. LM386 IC has been in use for decades and is still being used as Amplifier in Computer speakers and small Portable Stereos.
Pin Diagram of LM386
LM386 is a low voltage power amplifier with an inactive power draw of 24mW, which makes it suitable for battery controlled applications. The most common package for LM386 is an 8 – pin DIP. The following image shows the pinout diagram of the IC LM386
.From the pin diagram, it is clear that LM386 is a simple Amplifier IC with possibly minimum external connections. The following table shows the functions of each pin in the LM386 Amplifier IC.
Pins 1 and 8 are Gain Control Pins. By default, the Gain of the LM386 Amplifier is set to a factor of 20. When a capacitor is placed between pins 1 and 8, it bypasses the internal resistor (which is responsible for setting the gain to 20) and increases the gain to 200.
Pins 2 and 3 are the inverting and non – inverting inputs of the amplifier (internally, they are connected to an OP-AMP). Audio input from devices like microphone, mobile phones, laptops, etc. is given through these pin.
Working of LM386 Audio Amplifier Circuit
- A simple but efficient Audio Amplifier is designed using LM386 Audio Amplifier IC. The working of the circuit is very straight forward as all the work is done by the LM386 IC itself.
- When the system is powered on and proper audio input is given at the input, the LM386 Amplifier the input signal by a factor of 200 and drives the output speaker.
- One of the main problems with audio amplifiers like LM386 is the noise. Surprisingly, even though the circuit is built on a breadboard, there was very less noise from the speaker.
· LM386 is already one of the important IC in audio department and is featured commonly portable speakers and laptop speakers.
· They can also be used in TV Sound Systems, Line Drivers, Servo Drivers, Ultrasonic Drivers, etc.
· The LM386 Audio Amplifier Circuit can be used for recording voice from microphone, building small speakers that are battery operated, in FM Radio Devices, etc.
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source - electronicshub.org