18WuD2x

252 electrostatic field intensity • electrostatic stress
electrostatic field intensity An expression of the
strength of an electrostatic field. Usually expressed
in volts per meter, millivolts per meter, or
microvolts per meter.
electrostatic flux The flux existing around an
electric charge or a charged body.
electrostatic focusing In a cathode-ray tube, electron-beam
focusing achieved by varying the dc
bias voltage on a focusing electrode. Compare
ELECTROMAGNETIC FOCUSING.
electrostatic galvanometer A galvanometer operating
on the principle of the electrostatic voltmeter.
electrostatic generator A device for producing
high-voltage electric charges; e.g., a Van de
Graaff generator.
electrostatic headphone A device similar to an
electrostatic speaker, but held against the head
for private listening. Incoming audio signals
cause attraction and repulsion among charged
plates, resulting in acoustic vibration.
electrostatic hysteresis The tendency of some dielectrics
(especially ferroelectric materials) to saturate
and retain a portion of their polarization
when an alternating electric field to which they
are exposed reverses polarity. This causes the
charge to lag behind the charging force.
electrostatic induction The charge acquired by a
body inserted into an electric field. Compare
ELECTROMAGNETIC INDUCTION.
electrostatic instrument See ELECTROSTATIC
VOLTMETER.
electrostatic lens An assembly of deflecting plates
or cylinders, whose electric field causes an electron
beam to converge or diverge in much the
same way as a visible light beam passing through
an optical lens. Compare ELECTROMAGNETIC
LENS.
electrostatic loudspeaker See ELECTROSTATIC
SPEAKER.
electrostatic memory A memory unit in which an
information bit is stored as an electric charge.
electrostatic memory tube A cathode-ray tube in
which information bits are stored in capacitive
cells swept by the scanning electron beam.
electrostatic microphone See CAPACITOR MI-
CROPHONE.
electrostatic phase shifter See PHASE-SHIFTING
CAPACITOR.
electrostatic potential In an electric field, the potential
energy represented by the voltage between
the two elements creating the field, or between
any two points within the field.
electrostatic precipitator See DUST PRECIPITA-
TOR.
electrostatic printer A computer output peripheral
in which the printing medium, a fine dust, is
fused by heat onto paper that has been charged
according to the data being represented.
electrostatic process 1. Any process that uses
electrostatic action. 2. A method of photography
in which visual images are converted to electrostatic
images.
electrostatic recording A method of recording
that employs a signal-controlled electric field.
electrostatic relay A high-input-impedance relay
consisting of two polarity-controlled contacts; opposite
charges on the contacts close the relay,
and like charges open it.
electrostatics The branch of electricity concerned
with electrical charges at rest. Compare ELEC-
TRODYNAMICS and ELECTROKINETICS.
electrostatic screen A shield against electric flux
consisting of a number of straight, narrowly separated
rods or wires joined at only one end. The
shield has little effect on magnetic flux. Also
called Faraday shield.
electrostatic separator A device for separating
fine particles from a mixture by exposing the mixture
to an intense electrostatic field.
electrostatic series A list of materials arranged in
this sequence: any one of them becomes positively
electrified when rubbed with another lower
in the list, or negatively electrified when rubbed
with another higher in the list. Compare ELEC-
TROMOTIVE SERIES.
electrostatic shield Any metallic enclosure designed
to confine an electric field.
electrostatic speaker A loudspeaker whose vibrating
diaphragm is one of two plates in a large
air-dielectric capacitor, the other being a closely
situated metal plate (or plug). An audio voltage
applied to the plates causes them to vibrate. Also
called capacitive loudspeaker and capacitor loudspeaker.
electrostatic sprayer An equipment for spray
painting in which fine droplets of paint are attracted
by an electrostatic field to the surface to
be coated.
electrostatic storage See ELECTROSTATIC MEM-
ORY.
electrostatic stress 1. Stress in the vicinity of a
charged body or particle. 2. See DIELECTRIC
STRESS.