18WuD2x

Boltzmann’s principle • booster 81
statistical equilibrium, the number of particles in
any portion of the field is given by:
N E = N
–E/kT 0e
where E is the potential energy of a particle in the
observed area, N 0 is the number of particles per
unit volume in a part of the field where E is zero,
k is the BOLTZMANN CONSTANT, T is the absolute
temperature of the system of particles, and e
is approximately equal to 2.718.
bombardment The usually forceful striking of a
target with rays or a stream of particles.
bond 1. An area in which two or more items are securely
and intimately joined. 2. The attractive
force that holds an atomic or subatomic particle
or particle group together.
bonded-barrier transistor A bipolar transistor in
which the connection at the base region is alloyed.
bonded negative-resistance diode A diode that
displays a negative-resistance characteristic over
part of its current curve. This results from
avalanche breakdown.
bond energy In a molecule, the energy necessary
to break an atomic bond.
bonding 1. The formation of bonds between adjacent
atoms in a crystalline material, such as a
semiconductor. See specifically COVALENT
BINDING FORCES, IONIC BINDING FORCES,
and METALLIC BINDING FORCES. 2. The secure
fastening together of conducting surfaces, as by
soldering or brazing, to produce a high-conductance,
leak-free continuum.
bond strength The minimum stress required to
separate a material from another to which it is
bonded.
bone-conduction transducer A device used in
place of the earphone in a hearing aid to convey
sound energy to the bone structure of the head.
Bongard problem A method of evaluating how well
a machine vision system can differentiate among
patterns. Similarities and differences are noted
between objects in two sets of boxes. It was developed
for object-recognition systems, mainly for
use in intelligent robots.
book capacitor A variable capacitor in which the
metal plates are bonded along one edge and separated
from each other by means of mica sheets.
The capacitance is varied by opening and closing
the assembly book fashion. It is used as a padder
or trimmer.
Boolean algebra A system of symbolic logic. Statements
are represented as symbols, usually variables
such as x, y, and z. The logical AND operation
is represented by multiplication; the logical
inclusive OR operation is represented by addition;
the logical NOT operation is represented by
a minus sign or a line over the element symbol.
The system has rules, definitions and axioms via
which theorems can be derived. Used by engineers
in the design of digital electronic circuits.
Boolean truth table
AND NOT OR
x y xy x x + y
___________________________________________________
0 0 0 1 0
0 1 0 1 1
1 0 0 0 1
1 1 1 0 1
Boolean function In mathematical logic, a function
that makes use of BOOLEAN ALGEBRA.
Boolean theoreams
1. x + 0 = x (additive identity)
2. x1 = x (multiplicative idenity)
3. x + 1 = 1
4. x0 = 0
5. x + x = x
6. xx = x
7. (x’)’ = x (double negation)
8. x + x’ = 1
9. x’x = 0
10. x + y = y + x (commutativity of addition)
11. xy = yx (commutativity of multiplication)
12. x + xy = x
13. xy’ + y = x + y
14. x + y + z = (x + y) + z = x + (y + z)
(associativity of addition)
15. xyz = (xy)z = x(yz) (associativity of multiplication)
16. x(y + z) = xy + xz (distributivity)
17. (x + w) (y + z) = xy + xz + wy + wz (distributivity)
boom 1. A horizontal support for a microphone,
enabling the microphone to be suspended over a
sound source, but out of the sight of a camera.
2. A horizontal support for a small antenna that is
undergoing tests or sampling the field of another
antenna. 3. The supporting element in a Yagi,
quad, or log-periodic antenna. It establishes the
center of gravity and directional axis of the radiation
pattern. The driven element(s) and parasitic
element(s) are attached, usually at right
angles.
boost capacitor In the damper circuit of a television
receiver, the capacitor that is used to boost
the B-plus voltage. Also called booster capacitor.
boost charge A high-current, short-interval charge
used to revitalize a storage battery quickly. Also
called booster charge.
booster 1. Any device used to increase the amplitude
of a signal (e.g., as an amplifier or preamplifier)
or of an energy source (e.g., to boost the
output of a power supply). 2. A radio-frequency
preamplifier used ahead of a television receiver.