Introduction: 10W R.M.S. Audio Amplifier

                             The aim of the project was to make an audio amplifier that can deliver up to 10W R.M.S. power output. input can be given via computer/mp3 player or a mic (mic circuit explanation at the end). there are many different types of amplifiers tda2003 is probably a class b amplifier because its power consumption is quiet low then normal amplifiers and also that its noise is very low.
the purpose for which i chose this ic is that it has very less external components, very low distortion,very low input power and a corresponding high output power.

                          TDA2003 is a 10W car radio audio amplifier The device provides a high output current capability (up to 3.5A) very low harmonic and cross-over distortion. Completely safe operation is guaranteed due to protection against DC and AC short circuit between all pins and ground,thermal over-range,load dump voltage surge up to 40V

Step 1: Things Required

lists of components required to build the circuit


  • R1:220 Ω
  • R2: 2.2Ω
  • R3: 1Ω 1 watt
  • Rx: 39Ω                                  See the datasheet paw to alter the value of Rx
  • RV1: 10kΩ


  • C1: 2.2µF 25V electrolytic
  • C2:470µF 35V electrolytic
  • C3:0.1µF polyester or ceramic
  • C4:1000µF/35 V electrolytic
  • C5: 100nF polyester or ceramic
  • C6: 100µF 35v electrolytic
  • Cx 39nF                                       See the datasheet paw to alter the value of Cx


  • IC1: TDA2003
         :  connectors (cream shell connectors )
3-  2 pin connectors

Step 2: Helpful Material

Here is some helping material :
1- the data sheet of tda2003
2- the schematics of amplifier
3- and the PCB layout of amplifier

these circuits are modified ones the one i fabricated was a bit different .the difference was in placing the components not any thing else. if someone wants . datasheet open with any .PDF reader while the schematics and layout can be opened by Proteus (software) 7.0 or above.

Step 3: Circuit Diagrams

lets get started with the circuit the input form a computer or any other audio device will be given at the connector named as "input". u can even directly solder them if u want but connectors are easy to handle as they can be disconnected and reconnected without soldering and De-soldering except for the first time.

then the signal passes to the potentiometer named as RV1 it is just to control the input voltage and can be used as a volume control. c1 is a coupling capacitor and is used to block the dc portion present in the input signal.

c2 is present to reduce the distortion in the output as it is acting like a bypass capacitor (but u can see that there is 1ohm resistor except the ground so it is not actually the bypass cap.

c3 is there to reduce the ripple in the power supply and no other purpose similarly c6.

c4 is an output coupling capacitor . (i don't know the reason why it is there because it is reducing the BASS of the circuit never tried to reduce it if someone tries do tell me what happened).

we all know that there is a magnet and a coil in a speaker therefore they are inductive and inductors do not allow ac to pass through them that effectively so it is there to reduce the inductive effect of the speaker.

cx is present to reduce the higher frequency at the output terminal and also provide a feedback path to the amplifier.

                                    Connect a power supply 8-18V i recommend that u connect 16 V at least to get nice sound even when the volume is at its max u can purchase a power supply from the market OR u can use this link to make one for yourself
just replace the R2 and R22 resistors to 3k each to get +-16V (it was supplying +-12V)

at the output u can connect 2ohm/4ohm/8ohm Load to get 10W/8W/6W power respectively

Step 4: Demonstration Video & Modifications

here is a demonstration video :
don"t rely on this because the normal microphone of the mobile can not receive the bass so it seems that it has no bass but actually its base is awesome and also the video has distortion but actually the distortion is very low (zero below 50% volume) and negligible at 80% because the power supply is 12V if it was 16 or 18V then the distortion would be even less at high volumes .

another video

in case if someone wants to modify the circuit i.e.
increase/decrease bandwidth
increase BASS/treble
reduce noise
increase/decrease gain
the diagram shows how will the change in components affect these values

if u have any problem u can comment or mail me at
and rate it if u like it :)

Step 5: Mic Attachment (Optional)

Here is a modification if u want to amplify your sound that u speak connect a microphone
u will need
a microphone
a battery
a capacitor 1uF (try to use a non polarized capacitor)
a resistor 2.1k

and a connector to connect it to the input or u may simply solder it to the input of the amplifier
NOTE make sure that u connect the ground of the amplifier to the ground of the mic (to ensure common ground) otherwise it may not work properly
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