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Audio Amplifier Circuit with LM386



LM386 Amplifier:

Small Amplifiers are great for DIY Projects. This may be a Class AB amplifier like LM386 I.C. or it may be a Class D amp. Nowadays we all use Class D amplifiers most of the time because it is more efficient, Small size and most importantly the audio quality is also great. Today we are going to make a simple audio amplifier circuit with LM386 IC.

Circuit Diagram of the the Bass Booster Amplifier

The circuit Diagram is made with EasyEDA.com. LM386 is basically an OpAmp. The main work here for the amplifier is to amplify the audio signal. You can also check the LM386 datasheet Here. If you are a hobbyist then you should definitely try this simple circuit.

Simple audio amplifier circuit with LM386
Audio amplifier circuit with LM386

Printed Circuit Board (PCB) Layout:

Being a hobbyist, I made a simple Schematics for the project. I have designed a 2 layer PCB. Here I am showing the 2 Layouts of the PCB.

PCB Top Layer
PCB Bottom Layer

Needed components for LM386 Audio Booster:

  • LM386 IC
  • 8 Pin IC Socket
  • 100uf 25v, 10uf 63v, 1000uf 25v Capacitor
  • 1k, 4k7, 4R7 Resistor
  • 5MM LED
  • 100k Potentiometer
  • 2 Pin Screw Terminal Block

How does the amplifier circuit works?

This amplifier circuit is based upon Op-Amp. The IC is designed for comparing two different voltage. We use Op-amp for signal amplification subtraction or comparing 2 different voltages.

The schematics of the circuit will show you everything. The +ve input takes the audio signal. Here the reference -ve input is Grounded. So it means when the signal come out from the Op-Amp then it will be it’s multiplication factor.

The output signal comes through a capacitor in series. This capacitor captures hight frequencies. Some people use an inductor for this. you can also connect an inductor for the better audio experience.

The C3 Capacitor and the R1 Resistor are connected in series and it is grounded. The main purpose of this is to remove unwanted frequencies. Otherwise, you will find any type of humming noise from the amplifier.

Other components that are used are complementary components. You will find an example schematics of the circuit for any type of IC. there you will find any type of equation which is used for the IC. From that Equation, you can find the values of the Resistor, Capacitor, and other complementary components.

How to order PCB?

Go to PCBWAY.com and then click on Instant Quote. Now here are the basic settings for publishing a post.

  • First, select the PCB Dimensions. PCB way has a great deal when you order PCBs with 100mm x 100mm Dimensions. So, Just make the PCB file in the mentioned size for getting the offer.
  • Now you have to select the Number of PCBs you want to order. For prototype PCBs, you can order 5 Samples and upwards.
  • Now you have to choose the layers of the PCB. In most cases we for the Hobbyists the 2 Layer PCB is enough. In Old days we have only Single-sided PCBs that are not cost-effective and have to use more copper traces in comparison with the 2 layer PCBs. So, 2 Layer PCB is more than enough.
  • Now we have to choose the PCB Thickness. In general, they have set the thickness to 1.6mm which I think is more than enough.
  • Now you have to click on the Quote Now.
Instant PCB Quote

Submitting PCB Design to PCBWAY

Here is the typical PCB Submitting Page. You will find all types of PCB customizations here. Like Board Type, Size, Layer, Thickness, and much more.

  • PCBWAY supports multilayer PCBs such as 14 Layers PCBs also. Now you just need to upload the PCB.PCBWAY will take care of all the certain parameters of the PCB.
  • After that, it comes to the payment part. In this case, you can use any credit card, Debit Card, or PAYPAL. I would highly suggest you use any of the payment methods. there will be no issue. they have 128 bit SSL encryption on their server.
  • after a week you will receive your PCB and you can use the PCB to make a simple Audio Amplifier.

Let’s Make the LM386 Amplifier

Step 1:

Here I have received a total of 5 PCBs. Here we used panelized PCBs. Each PCB contains 4 PCBs. Because my PCBs are small, I made the schematics such that 4 PCBs fit in 100mm x 100mm Dimensions.

PCB Garber Link: Download

PCB Unboxing

Step 2:

I carefully broke 1 PCB from 4 Panellised PCB and placed it on the vice. On the PCB you will find all the THT components are mentioned. So, It will not be an issue to find the proper components for the PCB.

Simple PCB Amplifier

Step 3:

Next, I placed all the THT components on the PCB. Here you can see the PCB Looks. All components are very cheap and you can also get it in any local shop.

All Components on PCB

Step 4:

Here I have connected only one board of amplifier. So, this is a mono amplifier. From our phones and media systems, we get stereo output. but for this, we will only need one GND connection or one other Left/ Right channel for the mono signal.

MONO AMP Testing

Step 5:

Here I have made 2 mono boards this board. So, we can combine 2 mono boards and make the MONO Amp to a Stereo Amplifier. very easily. In this case in the audio in section, the Input Audio GND will be the same and the 2 different channels Left and the Right channel will go to the 2 different audio amplifiers.

2 Modules for Stereo

Step 6:

Here is the end result of the stereo amplifier. The LM386 amp works extremely great. and produces rich sound. The amp is only 1W capable of but the audio quality of the AMP will not depress you.

Stereo Amp Testing
Stereo Amplifier

The Bottom Line:

PCB Making is a fun project you can definitely make circuits boards so easily. No need too much experience. Some simple tutorials from the Internet and you are good to go for designing PCB. So, you must try Audio Amplifier Circuit with LM386.

You can also read our another article about Arduino Bluetooth control car


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