Audio Amplifier

I plan to use TDA2002V 8W Audio Amplifier for making a portable speaker.
What are its specifications?
Can I use it with a 4 ohm 5 W speaker

Did you Google it?

Amazing program this Google thingy!

Weedpharma

The TDA2002 can be replaced with the improved TDA2003.
Both ICs are ancient.
A class-D amplifier is much better suited for a portable (battery powered) speaker.
Search ebay for class-D amp boards. Some even come with bluetooth on board.
Leo..

Google ’ datasheet’ for any chip to find the datasheet. Works unless its an obscure
Japanese/Taiwanese/Chinese part.

SagarDev:
Can I use it with a 4 ohm 5 W speaker

Yes.

Russell.

So now an 8W amp can be used a 5W speaker, then can I use it with 10W ?

Depends on how much you like smoke.

Weedpharma

So now an 8W amp can be used a 5W speaker, then can I use it with 10W ?

Speaker power ratings are "complicated".

The power rating on the speaker is the "maximum program power".

A 10W speaker can be used with a 10W amplifier with normal voice/music that's hitting 10W on the peaks.

Normal program material has a peak-to-average ratio of about 10:1. That means a 10W speaker can handle about 1W average and you can burn it out with a 10W constant test tone, or with 10W or highly distorted music. (If you drive the amplifier into distortion, the average power goes up while the peak power stays about the same.)

For example, since electric guitar amps are often cranked into distortion it's generally recommended that the speaker be rated for twice the amplifier's power.

On the other hand, you can use a 100W stereo with 25W speakers as long as you don't blast the stereo at full volume...

Things get even more complicated with woofers, midranges, and tweeters. A "10 W" tweeter is designed to handle ONLY the high-frequency part of 10W program material.

And, some manufacturers "fudge" the specs... So a 10W amplifier may not really put-out 10W and a 10W speaker may not be able to handle 10W of normal program material...

The TDA2002, on a 12volt lead/acid battery, with a 4ohm load, outputs 3.2watt (10% distortion).
Leo…

Now Guys,

Can I run the TDA2002 with 9V?

The datasheet mentions 18V. Now half voltage means half power. So does the power reduce from 8W to 4W?

Now half voltage means half power.

No it doesn’t, do the math.

Now half voltage means half power.

Half the voltage (to the speaker) is 1/4 the power.

Power is calculated as Voltage x Current.*

And from Ohm’s Law, we know if we cut the voltage in half we will also cut the current in half… That’s 1/4 of the power.

There is some voltage-loss across the amplifier so when you cut the supply voltage in half the amplifier output-voltage usually gets cut by a little more than half.

  • Or, since Ohm’s Law gives you the relationship between voltage, current, and resistance -

Power = V2/R or Power = I2 x R.

If calculate amplifier power as V2/R, note that the theoretical maximum AC RMS voltage (with no voltage loss in the amplifier) is 0.354 x the DC power supply voltage. (With a bridge amplifier design you can double that for 4 times the power.)

There is also the possibility of it not working at all on 9V

LM386.
Amazing on a 9volt battery.

Which part of "get a class-D amp" didn't you understand.
Three AA batteries and this:

http://www.ebay.com/itm/2Pcs-3W-2-Mini-Digital-power-Audio-Amplifier-Board-USB-5V-Power-Supply-Arduino-/201498160558?hash=item2eea39edae:g:lOQAAOSw0HVWA5HQ

$0.50 each, shipped to your door.
Two 4ohm speakers (stereo, 2x3watt), or one with a double voicecoil (6watt).
No heatsink needed, because class-D is very efficient (longer battery life).
Leo..

Well, $2 each with shipping. Still, very cheap. And no additional shipping if you get more than one (pair). I'm tempted to order a bunch just to have them on hand.

See,

I have a 10W 8 ohm Woofer for this project. So I don't have a problem with the Wattage.

I have the problem with the Voltage Supply. I want it to be running at 9V or lesser.

SagarDev:
See,

I have a 10W 8 ohm Woofer for this project. So I don't have a problem with the Wattage.

I have the problem with the Voltage Supply. I want it to be running at 9V or lesser.

We all want things we can't have. You could use a DC-DC converter to step the voltage up to say, 12V. Then it would be easier to find an amp that would put out that amount of power.

SagarDev:
I have a 10W 8 ohm Woofer for this project.

I want it to be running at 9V or lesser.

Say you want an 8watt amp for this woofer.
You will need 8volt (RMS) for that.
That's 11.3volt peak. You need an amp that can provide 22.6volt p/p.
With the losses in the amp, I would pick a ~25volt supply.
About 30volt would be needed for 10watt output (in 8ohms...).
Perhaps now you understand why car stereo speakers are 4ohms, and bridged amps are used.
Leo..

So guys,

I solved the voltage problem with the help of aarg. Thank you…

Now I need the circuit to run this TDA2002V.