18WuD2x

624 shaker • shock-excited oscillator
shaker See VIBRATOR, 2.
shake table A platform, actuated by a vibrator, on
which components can be mounted for a vibration
test.
shallow-diffused junction A pn junction made by
diffusing the impurity material for a short distance
into the semiconductor wafer. Compare
DEEP-DIFFUSED JUNCTION.
shape factor 1. For a tuned circuit, the ratio of the
60-dB bandwidth to the 6-dB bandwidth. 2. For a
filter, the ratio of bandwidth at high attenuation
to that at low attenuation.
shaping network A combination of components for
changing the natural response of a circuit to a desired
response (i.e., a curve-changing circuit).
shared file A data file that is available for use by
more than one system simultaneously.
shared files system A data-processing system
having one direct-access storage device from
which information can be accessed by more than
one computer.
sharpener 1. A circuit or device for increasing the
selectivity of another circuit or device. 2. A circuit
or device for decreasing the rise or fall time of a
pulse or square wave. 3. A circuit or device for
steepening the response of a filter.
sharpness See SELECTIVITY.
sharp pulse A pulse having extremely fast rise and
fall times and narrow width (i.e., a spike).
shaving The physical modification of a phonograph
disc, or other permanent recording surface,
in preparation for rerecording.
S H band A section of the S BAND extending from
3700 to 3900 MHz.
sheath See POSITIVE-ION SHEATH.
shelf corrosion In a dry cell in storage, deterioration
of the negative electrode because of local action
in the zinc.
shelf life 1. The longest period of time that electronic
equipment can be continuously kept in
storage before deterioration of materials or degradation
of performance occurs. 2. The longest period
of time that a battery can be stored without
use before it must be discarded or recharged.
shell 1. An electronic orbit (imaginary shell) in an
atom. 2. The envelope of a component (e.g., the
outer casing of a power transistor or the housing
of a plug). 3. The rigid case in an audio or video
tape cassette.
shell-type choke See SHELL-TYPE INDUCTOR.
shell-type core A core that completely surrounds
the coil(s) of a choke or transformer.
shell-type inductor An inductor in which the core
completely surrounds the coil.
shell-type transformer A transformer in which
the core completely surrounds the coils.
shf Abbreviation of SUPERHIGH FREQUENCY.
shield A metallic partition or box for confining an
electric or magnetic field.
shield baffle A sheet-type shield. Also see BAFFLE,
2 and SHIELD PARTITION.
shield box A shield having a general box shape,
and which is usually enclosed on all sides.
shield braid Tubing woven from wire, through
which an insulated wire is passed and thus
shielded.
shield can A cylindrical shield, usually enclosed
on all sides.
shield disk A flat shield having a disk shape. Also
see BAFFLE, 2; SHIELD BAFFLE; and SHIELD
PARTITION.
shielded cable Cable completely enclosed within a
metal sheath that is either flexible or rigid.
shielded wire A single strand of insulated wire
completely enclosed in a flexible or rigid shield.
shield partition A wall-type shield usually consisting
of a single, flat sheet of metal, sometimes
bent into an angle. Also called BAFFLE SHIELD
(see BAFFLE, 2).
shield plate See BAFFLE, 2; SHIELD BAFFLE;
SHIELD DISK; and SHIELD PARTITION.
shield room See CAGE.
shield wire A (usually grounded) wire, near and
parallel to another wire that it shields.
shift 1. To move from one operating point to another
in a characteristic curve, or in the operation
of an equipment. 2. To transfer data from one
point to another in a system, or move it left or
right in a register.
shift flip-flop circuit A flip-flop designed especially
as a stage in a shift register.
shift pulse In a shift register, a drive pulse that initiates
the shifting of characters.
shift register In computers, calculators, and storage
systems, a circuit (usually composed of flipflops
in cascade) in which pulses can be shifted
from stage to stage and finally out of the circuit.
shingle-type photocell A device in which several
separate photocells are series connected by
slightly overlapping the ends of adjacent cells.
ship station A radio or radar station installed
aboard a ship that is not in port.
ship-to-shore communication Radio communication
between a ship at sea and a land-based station.
shock 1. See ELECTRIC SHOCK. 2. A signal applied
momentarily to a circuit, as in the shock excitation
of a tank. 3. A sudden, dramatic change
in an environmental variable (such as temperature).
4. Physical blows or vibration.
shock absorber Any object or device intended for
reducing physical vibration of a component, set of
components, circuit, or system.
shock device 1. A device for administering shock
therapy (see ELECTROSHOCK, 1). 2. An induction
coil and associated primary supply for applying
high voltage to a wire fence.
shock excitation Driving an inductance-capacitance
(LC) tuned circuit into damped oscillation
by momentarily applying a pulse.
shock-excited oscillator A type of self-excited oscillator
in which the transistor is suddenly cut off