1
GATE EE 2001
Subjective
+5
-0
The transistor in the amplifier circuit shown in the figure is biased at $${{\rm I}_C} = mA.$$ Use $${V_T}\left( { = {{kT} \over q}} \right) = 26\,mV,$$ $${\beta _0} = 2000,\,{r_b} = 0$$ and $${r_0} \Rightarrow \infty $$
$$(a)$$ Determine the AC small signal midband voltage gain $$\left( {{\raise0.5ex\hbox{$\scriptstyle {{V_o}}$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle {{V_i}}$}}} \right)$$ of the circuit
$$(b)$$ Determine the required value of $${C_E}$$ for the circuit to have a lower cutoff frequency of $$10Hz$$
$$(a)$$ Determine the AC small signal midband voltage gain $$\left( {{\raise0.5ex\hbox{$\scriptstyle {{V_o}}$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle {{V_i}}$}}} \right)$$ of the circuit
$$(b)$$ Determine the required value of $${C_E}$$ for the circuit to have a lower cutoff frequency of $$10Hz$$
2
GATE EE 2000
Subjective
+5
-0
A current amplifier has an input resistance of $$10\Omega ,$$ an output resistance of $$10\,\,k\Omega $$ and a Current gain of $$1000.$$ It is feed by a current source having a source resistance of $$10$$ $$k\Omega $$ and its output connected to a $$10\,\,k\Omega $$ load resistance. Find the voltage gain and the power gain
3
GATE EE 1999
Subjective
+5
-0
For the small signal $$BJT$$ amplifier shown in given figure. Determine at $$1$$ $$kHz$$ the following
$$(a)$$ $$\,\,\,\,\,\,\,\,$$ Quiescent collector current $${{\rm I}_{CQ}}$$
$$(b)$$ $$\,\,\,\,\,\,\,\,$$ Small signal voltage gain $${{{V_o}} \over {{V_i}}}$$
$$(c)$$ $$\,\,\,\,\,\,\,\,$$ Max. possible swing of the collector current.
4
GATE EE 1992
Subjective
+5
-0
For the $$JFET$$ amplifier shown in figure $$\mu = 100,\,{r_d} = 50k\Omega $$
$$(i)$$ Draw the $$AC$$ equivalent circuit
$$(ii)$$ Find the voltage gain of the amp
$$(i)$$ Draw the $$AC$$ equivalent circuit
$$(ii)$$ Find the voltage gain of the amp
Questions Asked from Small Signal Modeling (Marks 5)
Number in Brackets after Paper Indicates No. of Questions
GATE EE Subjects
Electric Circuits
Electromagnetic Fields
Signals and Systems
Electrical Machines
Engineering Mathematics
General Aptitude
Power System Analysis
Electrical and Electronics Measurement
Analog Electronics
Control Systems
Power Electronics