19 14 pts Follow the steps below to find the overall gain of

19. (14 pts) Follow the steps below to find the overall gain of the amplifier circuit shown. The AC source is 50 mV (rms) and has an internal resistance 7\'1 of 10 k 80V , v, v1 R1 The amplifier has an input resistance, of 3.1 k12, an output resistance r, of 60 k2, and a transconductance parameter g of 0.052 transconductance parameter g of0.052 Siemens. The load resistance R, is 9 k. (a) Write the formula for the input voltage to the amplifier v, in terms of the source voltage and calculate the input voltage. Ans.

Solution

a) from the voltage division formula.

vi=(50*10^-3*3.1*10^3)/(13.1*10^3)=0.01183 volts.

b) input current is=(50*10^-3)/(13.1*10^3)= 3.816*10^-6 amps.

c) io=0.052*vi=0.052*0.01183=6.1516*10^-4 amps.

e) current thrrough the load=iL=(6.1516*10^-4*60*10^3)/(69*10^3)=5.3492*10^-4 amps.

f) voltage across load vL=9*10^3*5.3492*10^-4=4.81428 volts.

g) voltage gain=VL/VS=(4.81428/(50*10^-3))=96.2856

current gain=(iL/iS)=(5.3492*10^-4)/(3.816*10^-6)=140.178.