18WuD2x

636 slide-rule dial • slotted line
slide-rule dial A dial mechanism having a straight
scale that resembles a slide rule.
slide switch A switch actuated by sliding a blockshaped
button. Compare BAT-HANDLE SWITCH,
PADDLE SWITCH, and ROCKER SWITCH.
on
slope detector An amplitude-modulation (AM) receiving
circuit detuned to one side of resonance
(i.e., to a point along the skirt of the selectivity
curve) to detect a frequency-modulated (FM) signal.
The FM swing occurs along the slope of the
resonance curve. Slope detection is useful in narrowband
FM when conventional FM circuitry is
not available.
off
slide switch
slide wire A simple potentiometer consisting of a
single, straight piece of resistance wire with a
sliding contact. Also see SLIDE-WIRE RESISTOR.
slide-wire bridge A simple four-arm bridge in
which the adjustable element is a single, straight
resistance wire along which a clip or slider is
moved, and that supplies two arms of the bridge
(one on each side of the slider).
slide-wire resistor A variable resistor consisting of
a single wire (straight or coiled) along whose
length a slider is moved to vary the resistance.
sliding contact A contact that mates with another
contact, or moves along a contacted surface, with
a sliding motion. Also called SELF-CLEANING
CONTACT and WIPING CONTACT.
slip 1. In an eddy-current brake, coupling, or
drive, the difference in speed between the field
magnets and the iron eddy-current ring. 2. In a
synchronous motor, the difference between rotor
speed and stator speed.
slip clutch In a gear or rack-and-pinion drive system,
a device that releases the load if the torque
becomes excessive. The gears then slip instead of
being damaged.
slip ring See COLLECTOR RING, 1.
slip speed See SLIP, 2.
slope 1. The slant of a line (graph) in rectangular
coordinates, depicted as the ratio of the change in
the dependent variable y to the change in the independent
variable x. If (x 1 ,y 1 ) and (x 2 ,y 2 ) are two
points on the line, then slope m is determined by
m = (y 2 – y 1 )/(x 2 – x 1 ). 2. The slant of a line in rectangular
coordinates as defined in 1, when the
line is tangent to a curve (graph) at a specified
point. 3. The skirt(s) of a selectivity curve, particularly
in a communications receiver, where a
small change in frequency results in a significant
change in gain or attenuation. 4. The ratio of the
extent of change in a quantity to the extent of
change in some other quantity, when a causal relation
exists between the magnitudes of the
quantities. Example: See SLOPE RESISTANCE.
slope resistance The ratio of a small change in
voltage to a small change in current at an electrode
or in a component.
slop-jar capacitor See WATER CAPACITOR.
slop-jar rectifier See ELECTROLYTIC RECTIFIER.
slot 1. In the armature of a motor or generator, a
groove in which the windings are laid. 2. The
notch in the response curve of a crystal filter.
slot antenna A microwave antenna that radiates
energy through a slot cut in a surface, such as
the metal skin of an aircraft.
slot cell A reinforcing, dielectric material (such as
plastic) placed in the slot of a ferromagnetic core.
slot coupling Coupling microwave energy between
a waveguide and a coaxial cable by means of two
slots, one in the waveguide and the other in the
outer conductor of the cable.
slot-discharge resistance See CORONA RESIS-
TANCE.
slot insulation 1. Insulation of wires in the slots of
the armature of a motor or generator (see SLOT,
1). 2. A material in the form of tape or sheets,
used for the purpose defined in 1.
slot radiator See SLOT ANTENNA.
slotted line A device consisting of a section
of air-dielectric coaxial line arranged for microwave
measurements. The outer conductor is
a metal cylinder, and the inner conductor is a
concentric metal rod. The cylinder is provided