Course code:EEC 214
Solved past question .
QUESTION ONE
- Define faithful application.
- State the principle of operation of JFET transistors.
- Of what advantage is the high input impedance of JFET.
- Compare in a tabular for the terminals of FET and BJT.
- State 5 advantages of FET.
- Use the figure below to answer question f and g.
- What is the role of the emitter by pass capacitor CE
- Select a suitable value for the emitter by pass capacitor for the circuit above if the amplifier is to operate over a frequency range from 2KHz to 10K
QUESTION TWO
a) Define the following terms and parameter for JFET.
I) AC drain resistance, r
ii) Irans conductance, g
iii) Amplification factor,
(b) State the relationship between the terms in (a) above.
(C) when a reverse gate voltage of 15V is applied to a JFET, the gate current is 10-3. Find the resistance between gate and source.
QUESTION THREE
a) Sketch the output characteristics of a FET transistor indicating the following,
(I) short-gate drain current.
(ii) Pinch off voltage.
(b) Write the expression for the drain current in FET.
(c) A JFET has the following parameters IDSS=32mA, VGS(OFF) =-8V, VGS=-4.5 find the value of the drain current, ID.
QUESTION THREE
(a) State three (3) application of JFET.
(b) State two (2) reasons for transistor biasing.
(c) In a transistor amplifier, when the signal changes by 0.02V the base current change by 10 and collector current by 1mA. If collector load Rc=5K and RD=10K find;
Current gain
Input resistance.
A.C load.
Voltage gain.
Power gain.
QUESTION FIVE
(a) What is Quiescent point?
(b) Define amplification
C(I) State three (3) transistor configuration you know.
(ii) identify the configuration in c(i) above that exhibit all type of gain.
(d) A change in drain voltage of 2V produces a change in drain current of 0.02mA. Find the A.C drain resistance.
QUESTION SIX
(a) Define the following terms;
(i) D.C load line.
(ii) A.C load line.
(b) Draw the circuit of a practical single stage transistor amplifier and explain the function of each component.