The pinsДЎ, 8 - Gain Pins 1 and 8 are used to adjust the gain level from the default 20x using specific values of connected capacitors.Дў - Negative Input 3 - Positive Input These are the standard op-amp inputs. The gain value can be adjusted if needed. It has a default gain of 20x - meaning it will multiply the voltage it receives on the input by 20 times, passing this through to the output. However it can, like most other basic audio amplifier chips, be used as a regular op-amp as well. which means its performance is based on the assumption that it will be driving speakers. The LM386 is an operational amplifier than has been specifically designed for use in audio applications. Let's take a look.ДЄ good place to start is the official datasheet (PDF) where you can get all the technical information you need. Also, you can pick one up for around $0.50 USD :) Here we'll learn about the chip and build a simple circuit to put it to work. means it's much loved by the DIY audio community and a terrific place to start experimenting with chip amps. available in the prototyping-friendly DIP package.This bad boy has been with us since 1983, and can still be found in low power, battery driven applications all around the world. Which brings us to the venerable LM386 by Texas Instruments. Typically they require few external components, can be prototyped with simple circuit designs and require less current than their discrete and tube counterparts. These ICs are collectively called audio amplifier ICs, amplifier chips or chip amps.

Like everywhere else, integrated circuits have made the barrier to entry much lower, letting us use any number of op-amps designed specifically for audio.

It used to be that audio amplification depended on large numbers of discrete components or power-hungry vacuum tubes to get decent sound from a source to a speaker. If you have access to an old speaker and an audio source (such as your phone or MP3 player) you can easily start building low cost circuits that have immediate results - music blasting into the airwaves. Which brings us to what is in my mind the best kickoff point in learning about audio electronics - amplification.

Reproducing, recording and amplifying audio gets you up close and personal with the electrons rocketing through your circuits. Audio is one of the most entertaining, time-consuming and (eventually) wallet-draining ways of learning about and falling in love with electronics.

Lm386 headphone amp schematic