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.
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hi sir, i wanted to know that what volt and what amp transformer is need to powerd this circuit
6V at 500mA should be enough.
Thank you for reply.
i do not found .1mfd capacitor or can i use 4inch 4ohm speaker. please help me...........
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.
hi dear
i m zee from pakistan or meri hobby be Electronics he . i m not profesnal. u help me in my hobby.
pls comment in my email address
What help do you need?
Give me a picture of the speker and could i use 6volt transformer to powering the circuit?
hi sir,i want to know that this circuits input signals are sterio/mono
Stereo.
hi sir ,i am found .5watt 8ohm 4inch speaker, can i use this speaker?
please reply...
hi sir,i am mistak the last comment,i write "found" but the right word is "get".
It's nice for this, but 0.5Watt is low sound.
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.......
The power supply you're using maybe insufficient. Try more rating transformer.
hi sir i can use 9volt 750 ma transformer
Yes, you can.
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..........................
what is diferent between TDA 2822 AND CD 2822 IC
Nothing. Chinese duplicate ICs are named with CD prefix. 😛
any problem to use cd 2822
Nothing. But if IC is heating, use a copper/aluminum heatsink on it. Goodluck.
where i fitting the heatsink please send the picture in my email my email id is "*************"
hi sir, i wanted to know that what is diferent between TDA 2822 IC OR CD 2822.
***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..****
Check if IC is heating or not. I suspect that the IC is damaged.
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**
For heating problem: Use lower voltage supply such as 6V, and use a heatsink
For single channel operation: Check connections and circuit build.
Ata ki headphone amplifier hisabe use kora jabe???
Kora jabe.
Thanks for the circuit Arup. This is precisely what I am looking for. Will attempt this little project and give feedback.
where can i get the datasheets for amplifier circuit
There is no thing as "datasheets for amplifier circuit". You can only get datasheets for any particular IC or other devices.
sir please reply
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.
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!