Miniature USB powered amplifier circuit for Laptops

Miniature USB powered amplifier circuit for Laptops

There’s been a strategy in market of buying USB powered speakers for laptops. These speakers usually drives power from one available USB port and inputs audio signal from headphone port, thus consuming two ports of a notebook. Lets see how much output these kind of speakers can give.

A USB port delivers maximum 500mA current and at 5Volts, it comes to max 0.5×5=2.5Watts. So, if our circuit eats 0.5-1Watts power, only 1.5Watt is left for speakers output.

Now you might ask 1.5watt wouldn’t create much sound. But believe me, under good conditions, this 1.5Watts is much more than expected. And this time we are going to use 0.5Watt-4Ohm x 2nos speakers.

These speakers are flat type having magnet inside them, and available at wholesale electronics shop in around 30rs per piece. For speaker box, use old jumbo matches box like homelite box. And for circuit, you need is an audio amplifier circuit capable of giving 0.5Watt output at each channel.

Here we will use a general purpose stereo amplifier TDA2822M IC, which comes in 8pin DIP package and usually found in mini walk-mans, etc. This IC can give up to 450 mW/channel with 4-ohm loudspeaker at 5V supply which is near our requirement.

The datasheet of TDA2822M can be downloaded in PDF format here (PDF, 362KB)


Use the stereo application circuit found in the datasheet i.e, the following. Then assemble it in a small(tiny) veroboard and complete the amplifier.
After making it, it may look like the one I made.

The expense in making this circuit is no more than 25 rupees. Hence the total cost becomes 30+30+25=85rupees, and if we add the cost of wires, jacks etc then it well fits under 100rupees. It’s a very cheap solution when USB speakers in market costs more than 300 rupees.

40 Comments

  1. Pharma829

    Hello! eaefged interesting eaefged site! I’m really like it! Very, very eaefged good!

  2. Saibal Roy

    hi sir, i wanted to know that what volt and what amp transformer is need to powerd this circuit

        • Saibal Roy

          i do not found .1mfd capacitor or can i use 4inch 4ohm speaker. please help me………..

          • Arup

            You can use that speaker but this circuit can’t power the full need of the speaker as those speakers are rated for 5watt RMS.

      • muhammad zeeshan

        hi dear
        i m zee from pakistan or meri hobby be Electronics he . i m not profesnal. u help me in my hobby.

  3. Saibal Roy

    Give me a picture of the speker and could i use 6volt transformer to powering the circuit?

  4. Saibal Roy

    hi sir,i want to know that this circuits input signals are sterio/mono

  5. Saibal Roy

    hi sir ,i am found .5watt 8ohm 4inch speaker, can i use this speaker?
    please reply…

    • Saibal Roy

      hi sir,i am mistak the last comment,i write “found” but the right word is “get”.

  6. Saibal Roy

    hi sir i have finish this project,but i face a problem, that is when i am increases the volume sound is buzzing and whan i decreases the volume the sound is good,please help me…….

    • Arup

      The power supply you’re using maybe insufficient. Try more rating transformer.

      • Saibal Roy

        hi sir i can use 9volt 750 ma transformer

          • Saibal Roy

            hi sir i am trid upto 9v 1A transformer but know improvment and next i am powered the circuit my laptop usb port but sound is more buzzing please help me……………………..

  7. Saibal Roy

    what is diferent between TDA 2822 AND CD 2822 IC

    • Arup

      Nothing. Chinese duplicate ICs are named with CD prefix. 😛

        • Arup

          Nothing. But if IC is heating, use a copper/aluminum heatsink on it. Goodluck.

          • Saibal Roy

            where i fitting the heatsink please send the picture in my email my email id is “*************”

  8. Saibal Roy

    hi sir, i wanted to know that what is diferent between TDA 2822 IC OR CD 2822.

  9. Milaan panda

    ***hey.,Arup,sorry 2 say dis…this circuits r not work.no sound is out 4m this cicuits.i don,t know what is proble..?plzz help me..****

    • Arup

      Check if IC is heating or not. I suspect that the IC is damaged.

  10. Milaan panda

    In this circuits..i am faceing some porblem.Ic is heated too much..&..it damaged many times.9volt ..1ap curent use 4 this circuits.3inch/4ohm speakers.another proplem is sound is out 4m only one side.another geting responce.***plzz help me**

    • Arup

      For heating problem: Use lower voltage supply such as 6V, and use a heatsink

      For single channel operation: Check connections and circuit build.

  11. Babin Basak

    Ata ki headphone amplifier hisabe use kora jabe???

  12. Sergio Momesso

    Thanks for the circuit Arup. This is precisely what I am looking for. Will attempt this little project and give feedback.

  13. sethu

    where can i get the datasheets for amplifier circuit

    • Arup

      There is no thing as “datasheets for amplifier circuit”. You can only get datasheets for any particular IC or other devices.

  14. Tomo (JP)

    Current Feedback Amplifier cirkit for TDA2822

    Hi! I am enjoying my TDA2822 mini-amp which has been modified to a Current Feedback Amplifier. By this modification, you can enjoy Hi-Fi sound with a cheap speaker set for PC etc. And much more in my case, the PC noise was disappeared completely!

    Modification is very simple.

    1) Connect the line from the cold(-) side (GND side) of the speaker not to the GND but to the cold (GND) side of C1.

    2) Insert a 0.3 ohm resistor between the cold(-) side of C1 and GND (in this time, the line from the speaker(-) is connected to C1 side of the 0.3 ohm resister).

    3) You can make the 0.3 ohm resister by relaxing a twisted electric wire. One thin wire composing a twisted electric wire may be about 0.3 ohm by 5-6 cm length.

    4) Do the same for another speaker and C2.

    5) For your reference, please see the second cirkit figure on
    http://www.urban.ne.jp/home/date/amp1/amp1.html
    where NJM2073 and TDA2822 are compatible.

    • Tomo (JP)

      If your speaker is 4 ohm, 0.3 ohm resistor is too much. 0.1-0.2 ohm would be better. If your speaker is 6 ohm or 8 ohm, 0.3 ohm resistor would be effective. Please cut and try!

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