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(ELEC202)pass_mt1.pdf
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THE HONG KONG UNIVERSITY OF SCIENCE AND TECHNOLOGY
DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING

Elec 202 Philip Mok
ELECTRONIC CIRCUITS II

Fall 2002 Room 2440
MID-TERM #1
(15 October 2002 4:35 pm - 5:50 pm)
Name: ________________________ Chinese Name: ______________________ Student No.: ________________________ Signature: ______________________ *Individual marks for each section are shown in [ ] brackets. Total = 40 marks.
(1) For the feedback amplifier circuit shown below, assume VBEon = 0.7 V and VA = . Find the collector currents IC1 and IC2 and voltage at nodes X, Y and Z for
(a)
= [6]

(b)
= 100. [8]



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(2)
For the amplifier shown below, all the transistors operate in active region with VBEon = 0.7 V, VT = 26 mV, = 100 and VA = 100 V.

(a)
Find the DC collector current IC1 and IC2 of Q1 and Q2, respectively. Do NOT assume = in the calculation. [4]

(b)
Use the values in part (a) to calculate the AC small signal parameters gm, r, re and ro of Q1 and Q2. [2]

(c)
Find the input resistance Ri, output resistance Ro, voltage gain vo/vi and current gain io/ii of the amplifier. [14]



(3)
An inverter and its DC transfer characteristic are shown below. Assume |VBEon| = 0.7 V and |VCEsat| = 0.2 V, = 100 and VA = .

(a)
Find the value of VOmin when VI = 5 V. [4]

(b)
What is the corresponding overdrive factor of the transistor? [2]





VCC = 5 V


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