Introduction: Powerful 3 Watts Mini Audio Amp!
Welcome to my instructable where in this tutorial i will show you how I made this small but powerful 1 watt audio amplifier which is very easy to make,requires very few external components and packs in a whole lot of power for the size of it!
So let's get started!
- IC 8002 audio power amplifier IC
- 10k resistors - 2
- 22k resistor - 1
- 0.1uF ceramic capacitor - 2
- Male header pins
- Veroboard or protoboard (or custom made PCB for this project which I have discussed later in this tutorial)
- 5V power supply (mobile phone chargers work just fine)
- 4 Ohm impedance speaker
- 3.5 mm headphone jack (for audio source to be easily plugged in)
- Soldering kit,multi-meter and accessories.
Step 1: Gathering All the Parts
As you can see that the project build is very simple and the number of components needed to make this are very minimal and can very easily be available at your local electronics store or laying around in you workbench!
Let's move on to the making of the circuit.
Step 2: Making the Circuit
the 8002 amplifier is an 8 pin IC available in SMD package and so making the circuit on a veroboard is a bit of a challenge. i decided to make the circuit layout and then generated the necessary gerber files so that the circuit can be fabricated easily.
Here I have attached the schematic diagram and my PCB layout in case you want to use the same.
Here is the link to the datasheet of the IC for easy reference:
Step 3: Fabricating the PCB
After designing the circuit , exporting the Gerber files and generating the necessary files for the CNC machine, it was finally time to fabricate the PCB using the isolation routing technique.
I was lucky to have a CNC machine which made my work very easy and I got the PCB real quick. You can always make your own PCB and make them by etching process of order them from a professional manufacturing house or even order them online nowadays.
I made 2 identical circuit boards in case I messed up the soldering process because soldering SMD components is always a challenge and we need to make sure the any unwanted shorts or improper soldering is avoided.
I have added the clips of the CNC milling in action in the tutorial video below. Make sure to check it out for more details!
Step 4: Completing the Soldering Process
The first step is to solder the IC in place making sure to avoid solder joints between adjacent pins or any other traces.We can then move on to soldering the rest of the through hole components in place making sure of the values.
The following pictures show what my circuit finally looked like.
Step 5: Testing of Any Faults or Unwanted Connections
After all the soldering job has been done, it is important to make sure that our circuit is error free. To do so we can use a multimeter in continuity mode and test out all the valid tracks and make sure of proper connectivity. Any shorts must be rectified by removing excess solder at the points and cleaning them thoroughly in order to remove impurities and residual flux.
Step 6: Choice of Speakers
As per the datasheet, the impedance of the speaker should be 3 ohms, 4 ohms or 8 ohms, using which we can get the power output as 3 Watts, 2.65 Watts and 1.8 Watts respectively. I had a few of them laying around and tested them with the amp and all of them work just fine.
For the final demo I used an old speaker from a stereo system.
Step 7: Making the Connectors of the Amp
In order to connect this module to power,audio source and speaker, I made these custom wires, one side of which was attached to female headers which fit into the header pins of the module. With this our setup is now complete and ready to be tested :)
Step 8: Final Look
This is my complete project. It is quite small and powerful at the same time. In comparison, it is almost the same form factor as an Indian 2 rupee coin. You can also power this circuit using a 3.7 V lithium ion battery as the IC supports a good range of operating voltage. Make sure not to exceed the max voltage recommended by the datasheet.
I hope you like this build!
Feel free to share your comments,feedback and doubts in the comments section below and do not forget to watch the video in the next step, and if you are there, consider subscribing to my channel as well.
Until next time :)