Page 96 - The Illustrated Dictionary of Electronics

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Boltzmann’s principle • booster 81

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