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(ELEC102)test2_pastn.pdf
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(20)
(3)
1
(3)
(9)
(5)
(300)
Text Box: Find the voltage gain VO / VS in terms of R , R1 , R2 , C and j.. . If the maximum voltage gain is 11 and
Text Box: Circuit is a low pass filter
1
0
8V
t
-7V
4.5ms
(5)
(10)
(4)
(19)
2
(10)
(a)
(9)
(b)
3
(7)
(a)
VZK = 7V
rZ = 5.
(7)
Text Box: Model of zener diode
Text Box: . In the ideal op amp circuit, the diode has the reverse characteristics as shown. Given that the diode equation is
Text Box: model
(26)
(12)
(c)
(8)
(b)
(6)
Text Box: If V1 = 13V, D is a breakdown diode
Text Box: If V2 = - 0.62V D is a ON diode
(14)
4
(14)
Vc = -11V
-
VC
+
3V
+ VO -
C
Text Box: Vo = 3V
(26)
(14)
(12)
4
(c)
5
(16)
e
(10)
1. EBJunction is a forward bias (on) diodeand BC is reverse bias (off) diode
2. E is very heavily doped(N +for NPN). E has many electrons,
3. B is very thin. So most electronsinjected from E (to B) are attracted to C and
Text Box: Draw the cross sectional structure of a NPN BJT transistor operated in the amplifier mode, describe the movement of
6
RC
RB
Vin (t)
Vi= 0.74V
+
VCE
-
Text Box: Given the BJT circuit and the IC - VCE curves of the BJT. (a) Draw the boundary of the cut-off, amplifier and
Boundary of the modes
IB = 0.12mA
IB = 0.08mA
Cutoff (or OFF)
Mode IB= 0
(7)
(7)
IB = 0.16mA
(a)
Text Box: a
Text Box: Amplifier (or active, linear) Mode VCE > VCESAT , IB > 0
Text Box: Saturation (or ON) Mode VCE = VCESAT
Vin1 = 0.76V
IB1= 0.12mA
Vin2 = 0.72V
IB2 = 0.04mA
Draw load line, Q point, and find voltage gain
(2)
(5)
(7)
(b)
(30)
(9)
(4)
(7)
(5)
(5)
(c)
(d)
(e)
Text Box: Maximum amplitude of Vo = 4V
Text Box: Q point = 14V
7
(8)
RC = 2k.
RB = 1k.
(8)
(25)
IC
(QorT)
VE
(QVE= IERE
~ ICRE)
VBE
(QVBE= Vin-VE )
IC
(QIC= IB )
IB
(9)
(a)
(b)
Text Box: (a) Explain briefly why the circuit can have stable IC if Vin is a constant . (b) Sketch the small signal (AC)
Text Box: Circuit can maintain stable IC (Q-point).
8
(20)
Text Box: . In the BJT circuit, . = 30, VBE(ON) = 0.7V, VCESAT = 0.2V Find IC/IB. Show clearly your reasons. (20)
Text Box: Hence BJT in saturation
(15)
ID
IS
source usually shorted to body
Metallic film
IG= 0
ID= IS
An NMOSFET consists of a metal gateinsulated from a p-type semiconductorsubstrate (or body) by an insulating layer of silicon dioxide. On either side of the gate there are n type regions forming the drain and source.
(10)
9
(5)
(a)
(b)
Text Box: (a) Name two advantages of MOSFET. (b) Draw the cross