Load Resistor in a MOSFET amplifier

[shaiqbashir]

Hi Guys!

well! i have designed a mosfet amplifier. This amplifier uses only MOSFET in its operation along with an input signal and capactors and resistors and VDD. I want to ask u one thing.

The amplifier which i have designed takes 0.1V of AC signal as an input and provides a gain of 3.3V/V. it is best for a load of 10K resistor. If i want to connect an 8-Ohm speaker as a load in place of 10K resistor, what modifications do i have to make. Plz help me.

Thanks a lot in advance

 

[SGT]

The gain depends on the load resistor. If you get a gain of 3.3 with a 10k load resistor, replacing it with a 8Ω resistor will drop dramatically the gain. What you need is another stage. I suggest you use a source follower (gain ~ 1) with the 8Ω charge at the source and no drain resistor.