# Electrical Circuits Question 1

ElectricalCircuits

Question1

Solution

Acequivalent circuit is constructed by assuming that all capacitanceshave zero impedance at signal frequency and dc voltage sources are acground

+

VI – 222.2K Ω16.5KΩ 16.5KΩ V0

16.5k//16.5k==222.2KΩ

Inputvoltage is applied to the gate terminal

Outputsignal appears at the drain terminal.

Sourceis common to both input and output signals. Thus circuit is termed aCommon-Source (C-S) Amplifier.

Theterminal gain of the C-S amplifier is the gain from the gate terminalto the drain terminal

Theterminal gain of the C-S amplifier is the gain from the gate terminalto the drain terminal

Avt==-gmRL

RL=r0||16.5||16.5.

Vcc=VG900V.

r0==250Ω.

RL=Rout=(++)-1=242.6Ω.

Rin=222.2KΩ.

VOV= VGS− Vt

gm=(2knId(1+lambdaVds)-1=0.9486ms

Picka value for Kn=0.6

Therefore,gm=0.9486ms

Vout/Vin=1.1

Question2

Solution

+

VI– 222.2K Ω 16.5KΩ16.5KΩ V0

16.5k//16.5k==222.2KΩ

Inputvoltage is applied to the gate terminal

Outputsignal appears at the drain terminal.

Sourceis common to both input and output signals. Thus circuit is termed aCommon-Source (C-S) Amplifier.

Theterminal gain of the C-S amplifier is the gain from the gate terminalto the drain terminal

Theterminal gain of the C-S amplifier is the gain from the gate terminalto the drain terminal

Avt==-gmRL

RL=r0||16.5||16.5.

Vcc=VG9V.

r0==250Ω.

RL=Rout=(++)-1=242.6Ω.

Rin=222.2KΩ.

VOV= VGS− Vt

gm=(2knId(1+Vdslambda)-1=8.849s

Vout/Vin= 242.6/222.2=1.1

Question3

Solution

+

VI-66.6K Ω 5k 10KΩ V0

100k//200k==66.6KΩ

Inputvoltage is applied to the gate terminal

Outputsignal appears at the drain terminal.

Sourceis common to both input and output signals. Thus circuit is termed aCommon-Source (C-S) Amplifier.

Theterminal gain of the C-S amplifier is the gain from the gate terminalto the drain terminal

Theterminal gain of the C-S amplifier is the gain from the gate terminalto the drain terminal

Avt==-gmRL

RL=r0||5k||10k.

Vcc=VG*3.5

r0=(0.05+3.5)/0.0007= 214.3Ω

RL=Rout=(++)-1=201.3Ω.

Rin=66.6KΩ.

VOV= VGS− Vt

gm=(2knId(1+Vdslambda)-1=8.849s

Vout/Vin=201.3/66.6=3

References

Reliabilityof High Mobility SiGe Channel MOSFETs for Future CMOS Applications.(2014). Dordrecht: Springer Netherlands.

Sobot,R. (2012). Wirelesscommunication electronics: Introduction to RF circuits and designtechniques.New York: Springer.