Page 75 - The Illustrated Dictionary of Electronics

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60 balanced method • balun

balanced method A system of instrumentation in balanced-to-unbalanced transformer See BALUN.
which a zero-center scale is used. The reading balanced transmission line See BALANCED LINE.
can be either side of the zero reading. balanced varactor tuning A two-varactor, back-
balanced modulator A symmetrical modulator cir- to-back circuit for adjusting the value of a ca-
cuit using bipolar transistors, field-effect transis- pacitor using an applied dc voltage. This
tors, an integrated circuit, or diodes as principal arrangement has an advantage over a single-
components, that delivers an output signal con- varactor (unbalanced) circuit, because high-
taining the sidebands, but not the carrier. It is tuned-circuit Q is maintained and harmonic
commonly used to generate a double-sideband generation is reduced.
(DSB) signal that can be filtered to obtain a balanced voltages In any symmetrical system,
single-sideband (SSB) signal. such as a balanced line or push-pull circuit, two
balanced multivibrator A switching oscillator cir- or more input or output voltages that are ad-
cuit in which the two halves are identical in con- justed to have the same amplitude and (usually)
figuration, and as nearly identical as practicable opposite phase.
in performance. balanced-wire circuit A circuit or conductor sys-
balanced network Any network intended to be tem with identical halves that are symmetrical,
used with a balanced system or balanced trans- with respect to ground and to other conductors.
mission line. It is characterized by a pair of ter- balancing circuit See BUCKING CIRCUIT.
minals, each of which shows the same impedance balancing coil In a receiver, a center-tapped an-
with respect to ground. tenna coil that is balanced to ground to eliminate
balanced oscillator A PUSH-PULL OSCILLATOR. MARCONI EFFECT.
balanced output Output balanced against ground ballast 1. A component that is used to stabilize the
(e.g., where the electrical midpoint of the output current flow through, or operation of, a circuit,
circuit is grounded). stage, or device. 2. An iron-core choke connected
balanced output transformer 1. A push-pull out- in series with one of the electrodes in a fluores-
put transformer with a center-tapped primary cent or other gas-discharge lamp.
winding. 2. An output transformer with a ballast resistor 1. A nonlinear inductive power re-
grounded center tap on its secondary winding. sistor whose voltage-current (EI) characteristic is
such that current through the resistor is inde-
pendent of voltage over a useful range. This fea-
ture enables the ballast resistor to act as an
automatic voltage regulator when it is simply
Input connected in series with a power supply and load.
Output 2. A small (usually high-resistance) resistor oper-
ated in series with a glow lamp, such as a neon
lamp, to prevent overload.
ballast transformer A misnomer often used in
place of BALLAST, 2.
ballistic galvanometer An undamped galva-
nometer that is used particularly to observe elec-
tric charges by noting the single throw resulting
from the momentary flow of current through the
galvanometer coil.
balanced output transformer, 2. ballistics The electronics-supported science con-
cerned with the motion of projectiles and similar
bodies in air or space.
balanced probe A probe, such as one for an elect- balloon antenna A vertical antenna consisting of a
ronic voltmeter or oscilloscope, that has a bal- wire or wires held aloft by a captive balloon. Occa-
anced input and (usually) a single-ended output. sionally, used by radio amateurs and shortwave
balanced-tee trap A wavetrap constructed in a T listeners at low and medium frequencies. A poten-
configuration, with a resonant section in each tially dangerous antenna because of large static-
conductor of a balanced transmission line. electric buildup, a tendency to attract lightning,
balanced telephone line A telephone transmis- the possibility of its breaking loose, and the risk of
sion line that has two sides, similar to a balanced accidental contact with high-voltage power lines.
radio-frequency transmission line. Either side balop Contraction of BALOPTICON.
has the same impedance, with respect to ground. balopticon An opaque-picture projecting system in
balanced termination A load device (or the prac- which the picture is viewed by a television (TV)
tice of using such a device) in which the sections camera, such as a vidicon, and displayed by a
provide identical termination for each of the sec- picture tube. Also called balop.
tions or conductors of a balanced system, such balun A specialized impedance-matching radio-
as a balanced line. frequency (RF) transformer. It is a wideband device,