課程名稱︰電子學一
課程性質︰物理系大二必帶
課程教師︰朱士維
開課學院：理學院
開課系所︰物理系
考試日期（年月日）︰2013/11/08
考試時限（分鐘）：180分鐘
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
(好讀版： http://www.ptt.cc/bbs/NTU-Exam/M.1384577233.A.ABC.html )
(範圍: CH0, Neaman CH1-2,5前半)
Electronics
2013 Fall Semester
Midterm
Duration: 180 minutes.
The marking scheme is shown in brackets before each question.
You are allowed to bring in a 1-page A4 size memorandum.
Only non-preprogrammed calculators may be used.
Assume every diode is ideal with 0.7 V voltage drop.
Be sure to explain vour choice.
1. [0] During our entire lifetime， interactions with various people are
inevitable. It is vital to show mutual
respect in these interactions. One of the key components in successful
interaction/communication is to
know others' names. So， please write down the name of our dear teaching
assistant (in Chinese or English， be sure you spell correctly).
2. [15] (a) [4] Does a capacitor belong to a linear
component? Why or why not? (b) [5] Find the
Thevenin equivalent circuit with respect to the
capacitor. (c) [6] (bonus) Then replace the
capacitor with a resistor chosen for maximum
power transfer. What is the value of the resistor?
What is the power absorbed by this resistor?
第2題圖形：http://i.imgur.com/LhfUI4E.jpg
3. [5] When we want to transfer a voltage signal from instrument A to
instrument B， what is the best combination of output resistance R
A
and input resistance R ? (l) R >> R (2) R ~ R (3) R << R .
B A B A B A B
Be sure to explain your choice.
4. [5] Can you explain why small signal is such an important concept in
Electronics?
5. [10] (a) [4] Is GaAs an intrinsic or extrinsic semiconductor?
(b) [6] For phosphorus doping in Si， what kind of doping is this?
Will the p+ ion result in increase of hole concentration?
Explain the reason.
6. [5] Which procedure does not increase the turn-on voltage of a pn
junction. (1) increase p-doping concentration; (2) increase n-doping
concentration; (3) increase temperature; (4) increase the contact
area of junction.
7. [5] Which one is the main conducting mechanism of a pn junction.
(1) drift of majority carriers; (2) diffusion of majority carriers;
(3) drift of minority carriers; (4) diffusion of minority carriers.
8. [10] (a) [5] When we apply an external voltage from n to p in a pn
junction， how does the depletion region change?
(1) wider; (2) narrower; (3) unchanged.
(b) [5] (bonus) Is that possible to make the depletion region completely
disappear with forward bias? Please discuss what is the consequence if the
depletion region is gone in a pn junction.
9. [25] (a) [5] This is a bridge rectifier on a circuit board along
with a RC filter. Without moving the relative position of each element，
please plot the circuit connection. (b) [5] Considering the input
voltage after transducer to be 12 V (amplitude) AC at 60 Hz， what is
the PIV of each diode? (c) [5] Following (b)， with R = 100 Ω ， if we
want the ripple voltage at output to be less than 100 mV， what is
the minimal value of C should we choose? (d) [5] following (c), what is the
total power consumption of the four diodes? (e) [5] If we add one more
Zener diode in the regulator with V = 10V and r = 0Ω
ZO Z
what is the maximal power consumption of the Zener diode?
(This Zener circuit R = 15 Ω)
第9題圖形1：http://i.imgur.com/cUzBTgo.jpg
第9題圖形2：http://i.imgur.com/2sxL6cz.jpg
10. [5] V (t) is a ±15 volt triangle wave. Select the appropriate pair
IN
of waveforms for V (t) and v (t) from the pairs shown below.
IN O
第10題圖形、選項：http://i.imgur.com/0vqfWYb.jpg
11. (Ex 2.36 & 2.39) [15] (a) [5] Please plot transfer characteristics for
this circuit. Please label the transition point and the slope of the curve.
(b) [5] If the DC part of v is -5V， V is OV， R = lkΩ，
I B
and diode current I = I [exp(v /v )-1],
D S D T
please find out the Q-point by drawing the load line plot.
(c) [5] Following (b), what is the equivalent small-signal resistance of the
-13
diode at this Q-point? (I =10 A)
S
第11題圖形：http://i.imgur.com/hv2TE3b.jpg
12. [15] (a) [5] If Vs = 0.01 sin(ωt) volt， what is the AC diode current
i ? (b) [10] As we have mentioned in class， when performing small-signal
d
analysis， 10% error between real component and linear model is the
maximum that we can accept. For the circuit below， what is the largest
amplitude of v to be treated as a "small-signal"?
s
第12題圖形：http://i.imgur.com/jVkhzkl.jpg
13. [5] Define the conditions for cutoff， forward-active mode， and
saturation mode for a pnp BJT.
14. [5] In a npn BJT which one is NOT the result of reducing the width
of base? (i) The diffusion of hole in base is higher; (2) β is larger;
(3) The speed of BJT is higher; (4) The gradient of minority carrier in
base is larger.
Please note that midterm corresponds to 25% in grades this semester， and
activeness in class is 10%. That is， if this problem set does not fit you
well， it will be a good idea to become more active in class.
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※ 編輯: ndpe1220 來自: 114.36.3.4 (11/16 13:33)