why coupling capacitors are used in Amp

[FMradio]

why Audio Amplifier has Coupling capacitors at its input & output ???
any good reason?

 

[ssankurathri]

capacitors at input block dc and allows ac only. so, none of the dc enters the circuit. They are called decoupling capacitors or blocking caps.
it is the same reason why they are used at output.

 

[hameeds01]

The Coupling capacitor prevents DC voltage bias from flowing back into the AC signal generator. In audio Amplifiers the coupling capacitors are used between the AC source and the DC voltage bias that passing almost all of the AC signal voltage on to the transistor while blocking all DC voltage.
don't 4get to press helped me
Regards
Engineer Hameed

 

[pranam77]

why Audio Amplifier has Coupling capacitors at its input & output ??? any good reason?

As the name of the amplifier itself indicates, the Audio is a form of AC which is amplified by the amplifier and finally fed in to the speaker. As the various stages of the amplifier are powered with DC it is mandatory to block the Dc and take the audio component for processing. Thus various capacitors are used to transfer the audio separated from DC. Cheers

 

[zlatkoMM]

And dont forget electrolite capacitor before speaker on
outout of amplifier replace one part of supply voltage to.

 

[ark5230]

And dont forget electrolite capacitor before speaker on
outout of amplifier replace one part of supply voltage to.

This is not clear, could you pleaes elaborate !

 

[zlatkoMM]

Sorry i forget to add :
IF you use only power suply with +Vcc and GND not simetrical supply load.

 

[LAKSITH]

In amplifier circuits the operating point (Q point) is decided by the DC supply value and the resistors involved. If it weren't for capacitors, DC outputs could feed back to input of the amp and could change the Q point. Change of Q point could result in clipped output waveform. (Input capacitor)

Also, at the output, the capacitor filters out the AC signal & gives the required output (which is an alternate waveform/ AC).