Electronic Devices and Circuits

359 Pages·1972·4.201 MB·English

by  G. J. Pridham and N. Hiller (Auth.)

Electronic
Devices and Circuits
IN THREE VOLUMES
VOLUME 3
by
G. J. PRIDHAM, B.SC. (ENG.), C.ENG., M.I.E.E.,
M.I.E.R.E.
Principal Lecturer, Enfield College of Technology
PERGAMON PRESS
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Copyright © 1972 Pergamon Press Ltd.
All Rights Reserved. No part of this publication may be
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First edition 1972
Library of Congress Catalog Card No. 67-26692
Printed in Hungary
This book is sold subject to the condition
that it shall not, by way of trade, be lent,
resold, hired out, or otherwise disposed
of without the publisher's consent,
in any form of binding or cover
other than that in which
it is published.
08 016755 1 (flexicover)
08 016626 1 (hard cover)
Introduction
THIS is the third of three volumes written for aspiring professional
and technician engineers in the electronics industry. The three
volumes provide a comprehensive series on electronics suitable for
students on University Engineering Degree Courses and on Higher
National Diploma and Certificate Courses in Electrical and Elec-
tronic Engineering.
The traditional thermionic-valve approach to electronics is no
longer appropriate, and the extensive development of semiconduc-
tor devices has prompted the writing of these volumes and the
use of an integrated treatment for the two devices. Introductory
network theory and physics have been included to support these
topics.
N. HILLER, Editor
List of Symbols
a Attenuation coefficient (nepers)
A Area (metre2)
A Gain of an amplifier
/? Feedback ratio
/3 Phase change coefficient (radians)
B Flux density (tesla)
B Susceptance (siemens)
C Capacitance (farads)
c Velocity of light in vacuo (3x 108 m/s)
b Width of depletion layer
D Diffusion coefficient
D Electric flux density (coulombs/metre2)
e Base of natural logarithms
e Permittivity of free space (1/36X10-9
0
farads/metre)
e Relative permittivity
r
E Electric field strength (volts/metre)
E d.c. or r.m.s. value of e.m.f. (volts)
E Energy (joules or electron volts)
E Acceptor energy level (eV)
A
E Energy level of conduction band (eV)
c
E Donor energy level (eV)
D
E Fermi level (eV)
F
E Energy level of valence band (eV)
v
e Charge on an electron (1-6X 10~19 C)
e Instantaneous value of an e.m.f. (volts)
F Force (newtons)
LIST OP SYMBOLS
Frequency (Hz)
Propagation coefficient
Correlation coefficient
Conductance (siemens)
Mutual conductance (mA/V)
Efficiency (usually a percentage)
Magnetic field strength
Planck's constant (6-624X10"34 joule-
second)
Short-circuit current gain of a transistor
Input resistance of a transistor with output
short circuited
Output conductance of a transistor with
input open circuited
Voltage feedback ratio of a transistor with
input open circuited
Large signal common-base current gain
Large signal inverse common-base gain
d.c. or r.m.s. value of current (amp)
Moment of inertia
Maximum value of current (amp)
Leakage current in common base (amp)
Leakage current in common emitter (amp)
Instantaneous value of current (amp)
Laplace transform of current
Current density (amp/metre2)
90° operator
Coefficient of coupling
Boltzmann's constant (1-38X10"23 J/K)
Inductance (henrys)
Diffusion length
Subsidiary quantum number
Amplification factor of a valve or FET
Permeability of free space (H/m)
LIST OF SYMBOLS XI
Relative permeability
Mobility of an electron (metre2/volt-second)
Mobility of a hole (metre2/volt-second)
Momentum
Mutual inductance (henrys)
Magnetic quantum number
Effective mass of an electron (94X10-31
kg)
Effective mass of a hole
Spin quantum number
Principal quantum number
Number of turns
Number of acceptor impurity atoms per
cubic metre
Number of donor impurity atoms per
cubic metre
Electron density
Hole density
Number of charge carriers per cubic metre
in an intrinsic semiconductor
Power (watts)
Charge (coulombs)
Instantaneous value of charge (coulombs)
Resistivity (O-m)
Charge density (C/m3)
Resistance (Q.)
Dynamic resistance (Q)
Radius (m)
T parameters
Hybrid-?r parameters
Anode slope resistance
Drain resistance
Hall angle
Laplace operator
xii LIST OF SYMBOLS
T Absolute temperature (K)
t Time (seconds)
0 Magnetic flux (webers)
4> Instantaneous value of magnetic flux (we-
bers)
<t> Potential barrier
V d.c. or r.m.s. voltage (volts)
V Maximum value of voltage (volts)
V Instantaneous value of voltage (volts)
V Velocity (m/s)
X Reactance (Q)
Y Admittance (= 1/Z) (siemens)
Input admittance with output short circuited
yi
y Output admittance with input short circuited
Q
y/ Forward transfer admittance with output
short circuited
y Reverse transfer admittance with input short
r
circuited
V Electric flux (coulombs)
z Impedance (£i)
Z Characteristic impedance (£2)
0
CO Angular frequency (rads/s)
Where subscripts are used, upper case denotes d.c. values and
lower case r.m.s. values.
CHAPTER 1
Network Theory
IN THIS chapter the use of Laplace transforms for network analysis
will be discussed and filter networks analysed in more detail than
in the previous volumes.
1.1. Laplace Transforms and Their Applications
The Laplace transform of any function is defined by the relation
£[F(t)] = \~e-'F(*)dt
9
Jo
and once the differential equation(s) for any circuit has been set
up, a method of solution is to take the transforms of each side,
separate into partial fractions, and then evaluate the inverse of the
transforms.
It is not the purpose of this book to cover material that rightly
belongs to a mathematical treatise, but in the following examples
an indication of the mathematical background will be given.
1,1.1. Simple RL circuit with suddenly applied d.c.
For the circuit shown in Fig. 1.1, at any time / after the switch is
closed,
2 ELECTRONIC DEVICES AND CIRCUITS
i / R
FIG. 1.1. Simple RL circuit.
di
The transform of — is —io + si.
dt
The transform of i is i.
V
The transform of V is
s
Hence, taking transforms of both sides,
L( — io+si) + Ri = —.
s
If, at time t = 0, / = 0, then i = 0.
0
V
Therefore (Ls+R)i = —,
i.e. i =
Ls[s+(R/L)]
V (LjR LjR \
r(
7~ s+(R/L))
V /l
R s+(R/L)J-
\*
1
The inverse of is 1.
s
1
The inverse of is s~^L)
IsHW)]
NETWORK THEORY
Hence / = ^ - ( l - 6 W ),
R
This equation gives the current at any time t after the switch is
closed.
1.1.2. Series LCR circuit with suddenly applied d.c.
At any time t after the direct voltage V is applied, the equations
for the series LCR circuit shown in Fig. 1.2 are
Ll+»+h-r - >-t
■y-
-WV H5W^-
FIG. 1.2. RLC circuit.
The transforms of these equations are
L(-/ + si) + Ri+~ = —
0 C s
and i = —q +sq.
0
If at time t = 0, # = / = 0, then i = qo = 0.
0
- <7 F
Hence (Z,y+2fy' + £■ = —
and
i = sq.