18WuD2x

ubble memory • bulk effect 89
netic material is divided into regions that are
magnetized in different directions. So called because
the flux lines of the tiny magnetized regions
are shaped somewhat like, and move around after
the fashion of, bubbles on the surface of a
glass of soda.
bubble shift register A shift register that uses a
magnetic bubble (see BUBBLE MEMORY) that
can be moved sequentially from electrode to electrode
on a wafer.
bubbling See MOTORBOATING.
bucket A computer memory or a designated location
in such a memory.
bucking
The process of counteracting one quantity,
such as a current or voltage, via series or
parallel application of a similar quantity that has
opposite polarity (180 degrees out of phase).
bucking circuit 1. A circuit used to obtain bucking
action. The simplest form is a battery and potentiometer
that supply a variable voltage of
polarity opposite to that of the voltage to be
bucked. A more sophisticated form is an ac transformer,
the secondary of which is connected in
series and out of phase with the ac utility line. 2.
The zero-set circuit in an electronic voltmeter.
bucking coil A coil placed and positioned so that
its magnetic field partially or completely cancels
the field of another coil. Troublesome hum fields
sometimes are neutralized with such a coil.
bucking voltage See BACK VOLTAGE, 2.
buckling The warping of storage-battery plates, usually
resulting from excessive charge or discharge.
buckshot In an amplitude-modulated (AM) or single-sideband
(SSB) radio transmission, broadband
signal splatter caused by excessive modulation,
or detuned multiplier circuits.
buffer
1. An amplifier used principally to match
two dissimilar impedance points and isolate one
stage from a succeeding one in a cascaded system,
and thus to prevent undesirable interaction
between the two. 2. In a digital computer, a storage
site used temporarily during data transfers to
compensate for differences in data flow rates. 3.
In digital-computer operations, a follower stage
that is used to drive a number of gates without
overloading the preceding stage.
Unbuffered
input
Time
buffer, 2.
Buffered
output
buffer amplifier See BUFFER, 1.
buffer capacitor A high-voltage fixed capacitor
that is placed across a transformer secondary to
suppress voltage spikes and sharp waveforms—
especially when the input is a square wave.
buffer circuit 1. In a data system that uses a keyboard,
an electronic circuit that allows the operator
to type ahead of the data output. 2. See
BUFFER, 1, 2 and 3.
buffered output An output (power, signal, etc.)
that is delivered from the generating device
through an isolating stage, such as a buffer amplifier.
This arrangement protects the device from
variations in the external load. Compare UN-
BUFFERED OUTPUT.
buffer storage 1. A buffer that is used to interface
between data systems with different rates of
transmission. 2. See BUFFER, 2.
bug 1. Slang for WIRETAP, 1. 2. Slang for circuit
fault, 1. 3. A semiautomatic key that some radiotelegraph
operators use to send Morse code.
bug key See BUG, 3.
building-block technique The process of assembling
electronic equipment by quickly connecting
together already completed stages (in the form of
boxes or blocks) and supplying power and signals
to the setup. Also called modular technique and
modular construction.
building-out circuit A short section of transmission
line shunting another line; it is used for
impedance matching. Also called building-out
section.
buildup 1. The process whereby the voltage of a rotating
generator starts at a point that is determined
by the residual magnetism of the machine,
and gradually increases to a voltage representing
the point at which the resistance line crosses the
magnetization curve. 2. The (usually gradual) accumulation
of a quantity (e.g., the buildup of
charge in a capacitor).
bulb A globe-like container having any of a number
of characteristic shapes from spherical to tubular
and usually evacuated, for enclosing the elements
of an electron device, such as a vacuum
tube, gas tube, photocell, or lamp.
bulge 1. A nonlinear attenuation-versus-frequency
curve in a transmission line. 2. A localized nonlinearity
in a function.
bulk The body or mass of a semiconductor specimen,
as opposed to junctions within the specimen.
Current flows through a junction, but it can
also flow, more or less, through the mass of semiconductor
wafer into which the junction has been
formed.
bulk effect An effect, such as current, resistance,
or resistivity, observed in the overall body of a
sample of material, as opposed to a region within
the material or on its surface. Thus, a silicon
diode can display junction resistance (i.e., resistance
offered by a junction processed in a wafer of
silicon), as well as bulk resistance (i.e., the effec-