Simple 5W Audio Amplifier Circuit with C1815 NPN Transistor

How to Make a Simple 5W Audio Amplifier Circuit with C1815 NPN Transistor?

C1815 is a BJT Type NPN Transistor. Generally, the NPN Transistors are mainly used for Switching, Amplification. This example circuit is a basic example of Transistor Amplification. Not only C1815 but also you can also use any NPN Transistor you have lying around. The Amplifier output power may differ according to the Transistor rating. Here we will get a maximum of 5W output from the amplifier. For a general user, 5W Speaker is more then enough else if he is a heavy music lover.

Amplifier Working:

Every audio signal is more likely an oscillation. The amplitude of this oscillated signal is low when it is generated. Mainly we find this type of signal in Mobile Phones, laptops, and other media devices outputs. More likely this signal is suitable for driving small earphones headphones. Here we will increase the amplitude of the media signal and then connect it with a speaker for listening to the loud sound.

Components Needed:

  • C1815 NPN Transistor – 1
  • 10k Resistor – 1
  • 100uF Capacitor – 1
  • Small 5W Speaker – 1
  • 3.5mm Audio Jack – 1
  • 9V Battery – 1

Tools Used:

  • Soldering Iron
  • Soldering Paste
  • Nose Pliers
  • Wire Cutter
  • Breadboard

Circuit Diagram:

I designed the circuit schematics diagram on free online software EasyEDA.

How to Make it?

First, gather all the components as I mentioned earlier. Now attach all the components step by step. First, connect the Transistor’s collector and base with a 10k Resistor. Now take the 100uF capacitor and connect it’s -ve with. For the audio transmission, we will need a jack. Here I am using an old 3.5MM Jack from an old Headphone. You can also get this jack from online in a couple of bucks.

The circuit is ready to give power to the transistor. It is recommended to use any voltage between 5 to 12V. In the next run, a song from your media device and you are good to go. Now you can enjoy your shooting pleasant music with high volume.

PCB Layout:

PCB Fabrication File:

Here is the Gerber file for the PCB if you want to replicate the same thing.

Making Video:

This is the Video from Creative Creator that will help you to replicate the amplifier. Make Sure you Subscribe to our channel.


Lastly, I would say this is an easy circuit for electronics enthusiasts for making something new. If you are a beginner then you should definitely try making this and maybe you can make your first Boom Box with it. This is a Basic BJT NPN amplifier so it means that you can also use a more powerful amplifier with a more powerful transistor.