18WuD2x

470 negative exponent • negative resistance
to a negative power. Raising a number x to a negative
power –n means taking the reciprocal of the
number raised to the power n. That is, x –n = 1/x n ;
for example, 10 –2 = 1/10 2 = 1/100 = 0.01.
negative feedback Feedback that is out of phase
with the input signal. Also called INVERSE FEED-
BACK, DEGENERATION, and DEGENERATIVE
FEEDBACK. Compare POSITIVE FEEDBACK.
Input
+
−
+V cc
Feedback
resistor
negative feedback
Output
negative-feedback amplifier An amplifier in
which negative feedback is used to improve performance
or modify response.
negative function A trigonometric function having
the negative sign. In a rectangular coordinate
system, the sine function is negative in the third
and fourth quadrants, the cosine in the second
and third, and the tangent in the second and
fourth. Compare POSITIVE FUNCTION.
negative gain A misnomer for FRACTIONAL GAIN,
arising because fractional gain can be expressed
in negative decibels.
negative ghost In a television picture, a ghost with
negative (see NEGATIVE, 4) shading.
negative ground In a direct-current power system,
the connection of the negative pole to common
ground.
negative image 1. A picture in which the blacks,
whites, and shades in between are the reverse of
those in the scene (see NEGATIVE, 4). 2. An abnormal
image that has the reverse shading described
in 1.
negative impedance An impedance that displays
the same behavior as that of NEGATIVE RESIS-
TANCE.
negative ion An atom with an excess of electrons
and, consequently, a net negative charge. Also
called ANION. Compare POSITIVE ION.
negative-ion generator A device for generating
negative ions and circulating them into the surrounding
air. This is believed by some people to
be beneficial to health.
negative lead See NEGATIVE CONDUCTOR.
negative-lead filtering Power-supply filtering in
which the choke coils and capacitors are in the
negative direct-current lead, rather than in the
positive lead (the usual position). One advantage
of this arrangement is the lower insulation requirement
of the choke.
negative light modulation In television image
transmission, the condition in which transmitted
power is increased by a decrease in the initial intensity
of light. Compare POSITIVE LIGHT MOD-
ULATION.
negative line See NEGATIVE CONDUCTOR.
negative logic 1. Binary logic in which a high negative
state represents logic 1, and a low negative
state represents logic 0. 2. Binary logic in which
a low positive state represents logic 1, and a high
positive state represents logic 0. Compare POSI-
TIVE LOGIC.
negative measurement error See NEGATIVE ER-
ROR OF MEASUREMENT.
negative modulation Amplitude-modulated television
transmission in which the transmitted
power decreases as image brightness increases.
Compare POSITIVE MODULATION.
negative modulation factor For an amplitudemodulated
wave having unequal positive and
negative modulation peaks, a ratio expressing the
maximum negative deviation from the average for
the envelope. Compare POSITIVE MODULATION
FACTOR.
negative number A real number less than zero
(i.e., one to which the minus sign is assigned).
negative peak The maximum negative instantaneous
current or voltage in an alternatingcurrent
waveform.
negative-peak voltmeter An electronic meter for
measuring the NEGATIVE PEAK voltage of an alternating-current
waveform.
negative phase-sequence relay A relay that responds
to the negative phase sequence in a
polyphase circuit. Compare POSITIVE PHASE-
SEQUENCE RELAY.
negative picture modulation See NEGATIVE
MODULATION.
negative picture phase In a television signal, the
picture-signal voltage swing from zero to negative,
in response to an increase in brightness.
Compare POSITIVE PICTURE PHASE.
negative plate The negative member of a battery
cell; electron flow is from the plate through the
external circuit.
negative pole See NEGATIVE ELECTRODE, 1, 2.
negative positive zero Abbreviation, NP0. Pertaining
to temperature-compensating capacitors having
a temperature coefficient of capacitance that
changes sign within a specified temperature range.
negative potential 1. The potential measured at a
negative electrode, with respect to the positive
electrode or to ground. 2. Potential less than that
of the earth as a reference.
negative resistance 1. A decrease in voltage across
a device as the current through it increases, and
an increase in voltage as the current decreases.
2. A decrease in current through a device as the