Page 90 - The Illustrated Dictionary of Electronics

5059F-pB_56-92 4/9/01 4:45 PM Page 75

biofeedback monitor • Birmingham wire gauge 75

ness, anger, etc., these monitors might be of bipolar The condition of possessing two pole sets. In
value to people who wish to gain improved control a conventional (non-FET) transistor, one pole set
of their emotions, and thus perhaps minimize the exists between the base and collector, and another
physiological effects of stress. pole set exists between the base and emitter.
biological robot Believed by some researchers to bipolar driving unit A magnetic headphone or
be possible, but not yet a practical reality: A living loudspeaker in which both poles (north and
organism created by biological cloning, whose south) of a magnet actuate a diaphragm or lever.
brain has been programmed exactly as a com- bipolar operation See AUTOMATIC POLARITY.
puter is programmed. bipolar transistor A two-junction transistor whose
biological shield An absorbent shield that blocks construction takes the form of a pnp or an npn
or attenuates ionizing radiation to protect per- “sandwich.” Such devices are current-operated,
sonnel working near radioactive materials. compared with field-effect transistors, which are
bioluminescence 1. The emission of light by a liv- voltage-operated. The bipolar transistor (of which
ing organism. 2. The light itself so produced by the familiar npn and pnp types are examples)
living organisms. uses both electron and hole conduction.
biomechanism An electromechanical device that biquinary code A variety of binary-coded-decimal
simulates the workings of some part of a living notation in which seven bits are used to repre-
being’s body. Examples are electromechanical sent each decimal digit. A number is written in
hands, arms, and legs. Such a device is often dif- two groups of bits: a two-bit group followed by a
ficult to distinguish from its biological counter- five-bit group. The positional values are 5 and 0
part when obscured by clothing. for the two-bit group, and 4, 3, 2, 1, and 0 for the
biomechatronics A contraction of the words biol- five-bit group.
ogy, mechanics and electronics. Research, devel- biquinary decade A decade counter that consists
opment and manufacturing that encompasses of a binary stage, followed by a quinary stage.
aspects of all three fields. This is especially im- bird 1. Slang for orbiting SATELLITE. 2. Slang for
portant in robotics. guided missile.
biometrics Mathematics, and in particular, statis- birdie 1. A spurious beat note in a superhetero-
tics and probability, applied to biology. dyne receiver. So called because of the character-
biometric security system An advanced intru- istic chirping sound it makes as the operator
sion-prevention system that measures biological tunes by the frequency on which it occurs. 2. A
characteristics of the people who are authorized parasitic oscillation in a radio transmitter, also
to enter a property. Such a machine can employ called a spurious emission or spur.
vision systems, object recognition, and/or pat- Birmingham wire gauge Abbreviation, BWG. Also
tern recognition to check a person’s face. The ma- called Stubs gauge. A method of designating the
chine might use speech recognition to identify various sizes of solid wire. BWG diameters are
people by the waveforms of their voices. It might somewhat larger than corresponding AMERICAN
record a hand print, a fingerprint, or an iris print, WIRE GAUGE diameters for a given wire-size
or a combination of all these things. A powerful designator.
computer analyzes the data obtained by the sen-
sors and determines whether the person is au- Birmingham Wire Gauge (BWG) Diameters
thorized to enter the premises. BWG Millimeters Inches
bionics The study, design, and application of mi- 1 7.62 0.300
croelectronic systems that simulate the functions 2 7.21 0.284
of living organisms. 3 6.58 0.259
biotelemetry The use of telemetry to collect data 4 6.05 0.238
from living organisms or to direct their move- 5 5.59 0.220
ment. 6 5.16 0.203
biotelescanner An instrument that monitors body 7 4.57 0.180
functions via radio, from a great distance. 8 4.19 0.165
Biot/Savart law A principle of electromagnetism 9 3.76 0.148
that expresses the intensity of magnetic field H in 10 3.40 0.134
the vicinity of a long, straight wire carrying a 11 3.05 0.120
steady current I. The basic formula is H = 2I/r, 12 2.77 0.109
where H is in oersteds, I is in amperes, and r is 13 2.41 0.095
the distance in centimeters from the wire. 14 2.11 0.083
bip Abbreviation of binary image processor. 15 1.83 0.072
biphase half-wave rectifier An alternative term 16 1.65 0.064
for FULL-WAVE RECTIFIER; also, each leg of a 17 1.47 0.058
two-diode full-wave rectifier. 18 1.25 0.049
BIPM Abbreviation of International Bureau of 19 1.07 0.042
Weights and Measures. 20 0.889 0.035