Most Important Symbols, Units, Constants, and Abbreviations
Note: Owing to historical reasons some symbols have multiple, context-dependent meaning.
‡
convolution integral (binary oper.);
complex conjugate (superscript)
A
ampere, basic SI unit of el. current
E
K
conductance, K œ "ÎV
Ka=b
function in complex frequency
domain, step resp., Ka=b œ J a=bÎ=
amplification; amplitude; area, [m# ]
gm
mutual transconductance
Ev
voltage amplification
ga>b
Ec
current amplification
function in time domain, usually
step response, ga>b œ 2a>b‡0 a>b
+
acceleration, [mÎs2 ]
H
unit of inductance, [H, henry],
[H] œ [VsÎA]
AC
alternating current
L a=b
C
unit of charge, coulomb, [C] œ [As];
constant of integration
Heaviside function in complex
frequency domain, L a=b œ "Î=
2a>b
Heaviside function, unit step
G
capacitance [F, farad];
contour of integration
M
current amplitude [A, ampere],
(DC or a complex phasor)
G)
thermal capacitance, [WsÎK]
i
index (subscript)
c
light propagation velocity,
299 792 458 mÎs
3
instantaneous current [A, ampere]
CD
critically damped system,
all poles real and coincident
4
imaginary unit, È"
K
kelvin, absolute temperature,
0 K œ 273.15 °C œ 459.67 °F,
?X [1K] œ [1°C] œ [1.8 °F]
5
magnetic field coupling factor of a
coil; counting index
5B
Boltzmann constant,
1.38 × 1023 VAsÎK
kg
kilogram, basic SI unit of mass
P
inductance, [H, henry], [H] œ [VsÎA]
_ef
direct Laplace transform
DC
direct current
H
circle diameter
.
distance, [m]; wire diameter, [m]
I
electric field strength, [VÎm]
Ig
energy gap, [eV] (in semiconductors)
e
Euler (natural) number,
2.718 281 828 459 045á
eV
electron Volt, unit of energy,
1 eV œ 1.602 × 1019 VAs
_" ef inverse Laplace transform
F
farad, unit of capacitance,
[F] œ [AsÎV]
6
length of coil winding, [m]
J
force, [N, newton], [N] œ [kg mÎs# ]
Q
mutual inductance [H, henry];
modulus (magnitude)
J a=b
rational function in frequency domain
MFA
maximally flat amplitude
J a=b
rational function in complex freq.
domain, J a=b œ T a=bÎUa=b
MFED maximally flat envelope delay
0
frequency [Hz, hertz], [Hz] œ ["Îs]
0h
upper half-power frequency of a
non-peaking amplifier
0H
upper half-power frequency of a
peaking amplifier
0 a>b
function in time domain
(usually impulse response)
7
coil parameter
7e
electron mass, 9.1095 × 1031 kg
m
meter, basic SI unit of length
R
total number of turns of a coil
8
system order number (n. of poles);
specific number of turns (per unit
length) of a coil; capacitance ratio
T
electric power [W, watt];
>
time [s, second]
T8
polynomial of order 8
>r
rise time
:
pole (polynomial denominator’s zero)
?
U7
polynomial of order 7
real part of a complex variable;
part of a decomposed function
U"
transistor label
V
volt, unit of electric tension (voltage)
;e
electron charge, 1.602 × "!19 As
Z
voltage amplitude [V, volt],
DC voltage or phasor
V
resistance [H, ohm]
@
V)
thermal resistance, [KÎW]
<
incremental resistance;
radius of a circle
instantaneous voltage [V, volt];
imaginary part of a complex variable;
part of a decomposed function;
velocity, [mÎs]
res
residue (residuum [lat.])
W
watt, unit of power, [W] œ [VA]
rad
radian, unit of angle, [1 rad] œ
\
reactance, the imaginary part of
an impedance
s
second, basic SI unit of time
unit of conductance, siemens, ["ÎH]
B
general variable
S
=
complex frequency, 5  4=,
]
admittance (complex), ] œ "Î^
pole or zero of a transfer function
C
general function or operation result
=i
X
time constant, VG or PÎV;
temperature
^
impedance (complex), V  4\
D
complex variable; polynomial zero
!
current ratio 3c Î3e œ " Îa"  " b
.r
relative magnetic permeability
"
transistor current gain, 3c Î3b
#
product
?
difference
1
Ludolph number, 3.141 592 653á
$
overshoot [%]; spacing between
adjacent turns of a coil [m]
!
sum
5
real part of a pole
$a>b
Dirac function, ideal impulse
7
dummy time variable
&
electrical permittivity,
dielectric constant
7T
transistor time constant, "Î=T
&!
electrical permittivity of vacuum,
8.8542 × 1012 AsÎVm
7r
rise time
:
phase angle
360°
#1
&r
relative electrical permittivity
;
frequency ratio, =Î=h
(b
bandwidth improvement factor
(extension)
H
unit of resistance, Ohm
(r
=
rise time improvement factor
(decrease)
angular frequency, #10 ;
imaginary part of a pole
)
pole angle, arctana5 Î=b
=h
upper half-power angular frequency
of a non-peaking amplifier
.
magnetic permeability, . œ .! .r ;
mobility of charge carriers
=H
upper half-power angular frequency
of a peaking amplifier
.!
magnetic permeability of vacuum,
"Îa%1 × "!( b VsÎAm
=T
transistor transition frequency at
which " a=T b œ "
eef
imaginary part of a complex quantity
def
real part of a complex quantity