|
a |
alpha |
Temperature coefficient. Fine-structure constant. |
|
G |
Gamma |
reflection coefficient. |
|
d |
delta |
The loss-angle of a reactive impedance. d=90-f. A small change or increment. |
|
D |
Delta |
"the change in" (operator) |
|
e,
e |
epsilon |
Permittivity. Complex (i.e., includes losses) when bold. |
|
er,
er |
|
Relative permittivity. Dielectric constant |
|
h, h |
eta |
A ratio. A dimensionless transfer function. e.g., the relationship
between input and output for a network such as Vout/Vin. Efficiency. |
|
l |
lambda |
Wavelength = c/f, i.e., the speed of light divided by the frequency
in Hz. |
|
l' |
lambda prime |
Electrical wavelength, i.e., wavelencth when the effective propagation
velocity differes from c. |
|
m: |
mu (italic) |
parent mean. |
|
m,
m |
mu |
permeability. Complex (i.e., includes losses) when bold. |
|
mi |
|
Initial (low frequency) relative permeability of a magnetic material. |
|
mr,
mr |
|
Relative permeability. A dimensionless number which is multiplied
by m0 to obtain
the absolute permeability. |
|
n |
nu |
the number of degrees of freedom of a data set. |
|
X |
Xi |
AC resistance factor defined such that Rac
= Rdc X. |
|
p |
pi |
Ratio of circumference to diameter of a circle = 3.14159265....... |
|
r |
rho |
volume resistivity. |
|
r |
rho (italic) |
density. |
|
S |
Sigma |
summation operator. |
|
s |
sigma |
standard deviation |
|
s² |
sigma squared |
statistical variance. |
|
F |
Phi |
Proximity factor (proportionate increase in resistance due to
external fields). |
|
f |
phi |
Phase angle. Angle between an impedance vector and the resistance
(real) axis in impedance space. |
|
c |
chi |
Magnetic susceptibility. |
|
c² |
chi-squared |
The normalised square error sum. |
|
c²/n |
reduced chi-squared |
chi-squared divided by the number of degrees of freedom in the
data. |
|
W |
Omega |
Ohms (unit of resistance) |
|
w |
omega |
Angular frequency = 2pf [ radians
/ second ] |
|
A |
Amperes |
|
a |
graph intercept. Zero-order fitting parameter. |
|
AC |
Alternating current |
|
AL |
Inductance factor (Henrys per turn-squared) |
|
AGC |
Automatic Gain Control. |
|
ALC |
Automatic Level Control (particularly, carrier level of a radio
transmitter). |
|
AMU |
Antenna matching unit. |
|
ATU |
Antenna tuning unit. |
|
B |
Susceptance. The imaginary part of an admittance. |
|
BC |
The susceptance of a capacitor. BC = 2pfC |
|
BL |
The susceptance of an inductor. BL = -1/(2pfL) |
|
b |
Gradient of a regression line. First-order fitting parameter. |
|
C, C |
Capacitance. Complex (i.e., includes losses) when bold. |
|
C |
(italic) capacitance per unit length |
|
c |
Velocity of light = 299 792 458 m/s |
|
CRAB |
Capacitor ratio-arm bridge. |
|
CVS |
Capacitive voltage-sampling. |
|
D |
Denominator. Diameter of a cylinder or solenoid. |
|
d |
Differential operator. Diameter (of a wire, etc.) |
|
¶ |
("curly d") partial differential operator . |
|
DC |
Direct current |
|
DMM |
Digital multi-meter |
|
DVM |
Digital Voltmeter. |
|
E |
Energy |
|
e |
Euler's or Napier's number = 2.7182818....... |
|
ERP |
Effective rediated power. |
|
ESD |
Estimated Standard Deviation. |
|
ESL |
Equivalent series inductance. |
|
ESR |
Equivalent series resistance. |
|
F |
Farads (unit of capacitance). |
|
f |
frequency |
|
f |
(italic) function operator; e.g., y = f(x) |
|
FSD |
Full-scale deflection (of a meter). |
|
G |
Conductance. The real part of an admittance. |
|
H |
Henrys (unit of inductance). |
|
h |
height |
|
HF |
High-frequency. The short-wave radio spectrum between 1.6 and
30MHz. |
|
Hz |
Hertz (cycles per second). |
|
I, I |
Current phasor, Current. |
|
i |
(subscript) relating to current sampling. |
|
j |
(in bold) = Ö(-1) , the
90° rotation operator. |
|
k |
A constant or parameter. Boltzmann's constant. |
|
L, L |
Inductance. Complex (i.e., includes losses) when bold. |
|
L' |
(L prime) Inductance modified by the effect of self capacitance. |
|
L |
(italic) Inductance per unit length. |
, l |
length |
|
l' |
(l prime) Electrical length, i.e., lc/v |
|
LF |
Low frequency |
|
ln |
Loge , Naperian logarithm (operator) |
|
M |
Mutual inductance |
|
m |
metres (unit of length) |
|
MDB |
Magnitude-Difference
Bridge. |
|
N |
Numerator. A number. The number of turns in a coil. |
|
n |
Refractive index. The number of observations in a data set. An
arbitrary integer. |
|
P |
Power |
|
PF |
Power-factor |
|
Q |
Quality. The ratio of reactance to resistance of an impedance
in series form. |
|
R |
Resistance. The real part of an impedance. |
|
R |
(italic) Resistance per unit length. |
|
r |
radius |
|
R0 |
The characteristic resistance, or surge resistance, of a transmission
line. The real part of Z0. A reference
or standard resistance. The target or design load resistance. |
|
RF |
Radio frequency |
|
RFC |
Radio-frequency choke (an inductor intended to present a high
impedance at radio frequencies). |
|
RMS |
"Root Mean Squared". The equavalent direct current
or voltage which gives the same heating effect as an alternating
current or voltage. The magnitude of an average. |
|
Rr |
Radiation Resistance, That part of impedance which is associated
with energy radiated into space. |
|
RVS |
Resistive voltage-sampling. |
|
s |
seconds (units). An arbitrary scalar constant. |
|
S |
Siemens, W
(the unit of conductance, formerly known as the Mho).
SWR |
|
SRF |
self-resonance frequency. |
|
SWR |
Standing Wave Ratio. |
|
T |
temperature |
|
t |
time |
|
TP |
Test point. |
|
TRAB |
Transformer ratio-arm bridge. |
|
TVS |
Transformer voltage-sampling |
|
U, U |
Arbitrary mathematical function (complex when bold). |
|
V, V |
Voltage phasor (bold), Voltage, Volts. |
|
v |
(subscript) relating to voltage sampling. velocity. |
|
VCA |
Voltage-Controlled Amplifier. |
|
W |
Watts |
|
w |
width |
|
x |
An independent variable. |
 |
("x bar") sample mean. |
|
X |
Reactance. The imaginary part of an impedance. |
|
X0 |
The characteristic reactance of a lossy transmission line (always
negative). The reactance of a standard or reference capacitor. |
|
XC |
The reactance of a capacitor. XC = -1/(2pfC) |
|
XL |
The reactance of an inductor. XL = 2pfL |
|
Y |
Admittance. The reciprocal of impedance. Y = G + jB |
|
y |
A dependent variable. |
|
Z |
Impedance. Z = R + jX |
|
Z0 |
The characteristic impedance of a lossy transmission line. Z0 = R0 + jX0 .
X0 is negative. |
|
Z0 |
The impedance of free space (real for a Lorentzian vacuum, hence
not bold). |