Hello everybody, I have been currently reading the MOSFET chapter from Dr Sedra's book "Microelectronic circuits". There is an equation there that describes the voltage gain Av.
It is derived like that: first of all  output voltage vo=(igm*vgs)Rl (signal current  transcunductance*signal voltage at the gate)*load resistance
Next, there is an equation to describe the signal current i=(vgsvo)/Rg (signal voltageoutput voltage)/input resistance
And now is the problem, the author says that if we substitute for signal current i from the second equation into the first equation, then the voltage gain vo/vgs will be gmRl*[(1(1/gmRg))/(1+(Rl/Rg))]
So he arrives from here: vo=[((vgsvo)/Rg)gm*vgs]Rl to here vo/vgs=gmRl*[(1(1/gmRg))/(1+(Rl/Rg))]
I fail to understand which transformations does he do to arrive there, please guyz help me out!! In the 6th edition it is page 286 top.
It is derived like that: first of all  output voltage vo=(igm*vgs)Rl (signal current  transcunductance*signal voltage at the gate)*load resistance
Next, there is an equation to describe the signal current i=(vgsvo)/Rg (signal voltageoutput voltage)/input resistance
And now is the problem, the author says that if we substitute for signal current i from the second equation into the first equation, then the voltage gain vo/vgs will be gmRl*[(1(1/gmRg))/(1+(Rl/Rg))]
So he arrives from here: vo=[((vgsvo)/Rg)gm*vgs]Rl to here vo/vgs=gmRl*[(1(1/gmRg))/(1+(Rl/Rg))]
I fail to understand which transformations does he do to arrive there, please guyz help me out!! In the 6th edition it is page 286 top.
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