1) show that the presence of bypass capacitor in the circuit significantly enhan

Question

1) show that the presence of bypass capacitor in the circuit significantly enhances the gain in the mid-band region. In answering you may assume that the bypass capacitor creates a virtual ground at the capacitor. You may also ignore the coupling capacitors and the biasing resistors. In the small-signal model, assume that gm = 0.5 X 10^-3 S.

2) by looking at the data-sheet for VN2222LL, state the maximum allowed Drain-Source voltage for this transistor.

show that the presence of bypass capacitor in the circuit significantly enhances the gain in the mid-band region. In answering you may assume that the bypass capacitor creates a virtual ground at the capacitor. You may also ignore the coupling capacitors and the biasing resistors. In the small-signal model, assume that gm = 0.5 times 10^-3 S. by looking at the data-sheet for VN2222LL, state the maximum allowed Drain-Source voltage for this transistor.

Explanation / Answer

the voltage gain is =-gm*Rload.

here Rload=R3 || R6

so when the bypass capacitor is not present,

Ib=(Vbe-.7)/((B+1)*R5)

gm=Ic/Vt

so the gm decreases in absence of bypass capacitor.

when the R5 is sorted, the Ic increases, increasing the value of gm as Vt=.026 V

so gain increases as Rload is same in both cases.

2> nnnIt is 600 mA

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