Hello , I'm new .
I tried to control gain of TDA2822 amplifier but It look like has a fixed-gain amplifier.
I want to know what circuit need to design for it.
Can someone help me to build this project?

 

The gain can be set to 39 db or less with passive components, more more gain you would need another amplification stage.

What range of gain do you need and how do you plan to control the gain? Is a pot ok or does it have to be voltage controlled"

 

As above, the maximum forward gain is set by internal resistors to approx. 39 dB. You can reduce this with one resistor between an inverting input (pin 3 or 14) and its capacitor to GND.

If you want to vary the gain electronically, the 2822 does not lend itself to that type of circuit.

ak