Reduction in magnitude of
oscillation due to energy being
dissipated as heat.
darlington pair
An amplifier consisting of two
bipolar junction transistors
with their collectors connected
together and the emitter of one
connected to the base of the
other. Circuit has an extremely
high current gain and input
impedance.
DC
Abbreviation for "direct
current".
DC load line
A graph representing all
possible combinations of voltage
and current for a given load
resistor in an amplifier.
DC offset
The change in input voltage
required to produce a zero
output voltage when no signal is
applied to an amplifier.
DC power supply
Any source of DC power for
electrical equipment.
dead short
Short circuit having zero
resistance.
decade
A frequency factor of ten.
decibel
(dB) a logarithmic
representation of gain or loss.
degenerative feedback
Also called negative feedback. A
portion of the output of an
amplifier is inverted and
connected back to the input.
This controls the gain of the
amplifier and reduces distortion
and noise.
delay time
The time for collector current
to reach 10% of its maximum
value in a BJT switching
circuit.
depletion region
Thre area surrounding a pn
junction that is depleted of
carriers.
depletion mode
In a FET, an operating mode
where reverse gate-source
voltage is used to deplete the
channel of free carriers. This
reduces the size of the channel
and increases its resistance.
depletion-mode MOSFET
A MOSFET designed to operate in
either depletion mode or
enhancement mode.
device
A component or part.
diac
A two terminal bidirectional
thyristor. Has a symmetrical
switching mode.
dielectric
Insulating material between two
plates where an electrostatic
field exists.
dialectric constant
Property of a material that
determines how much
electrostatic energy can be
stored per unit volume when unit
voltage is applied.
dialectric strength
The maximum voltage an
insulating material can
withstand without breaking down.
differential amplifier
An amplifier in which the output
is in proportion to the
differences between voltages
applied to its two inputs.
differentiator
A circuit in which the output
voltage is in proportion to the
rate of change of the input
voltage. A high pass RC circuit.
diffusion
Tendency of conduction band
electrons to wander across a pn
junction to combine with valence
band holes.
digital
Relating to devices or circuits
that have outputs of only two
discrete levels. Examples: 0 or
1, high or low, on or off, true
or false etc.
diode
A two terminal device that
conducts in only one direction.
DIP
Abbreviation for "dual in line
package."
direct coupling
Where the output of an amplifier
is connected directly to the
input of another amplifier or to
a load. Also known as DC
coupling because DC signals are
not blocked.
direct current
Current that flows in only one
direction.
discharge
Release of energy stored in
either a battery or a capacitor.
discrete component
Package containing only a single
component as opposed to an
integrated circuit containing
many components in a single
package.
dissipation
Release of electrical energy in
the form of heat.
distortion
An undesired change in a
waveform or signal.
distributed capacitance
Any capacitance other than that
within a capacitor. For example,
the capacitance between adjacent
turns of wire in a coil.
distributed inductance
Any inductance other than that
within an inductor. Example
inductance in any conductor.
domain
A moveable magnetized area in a
magnetized material. Also known
as magnetic domain.
donor atoms
Pentavalent atoms that give up
electrons to the conduction band
in an N type semiconductor
material.
doping
The process of adding impurity
atoms to intrinsic (pure)
silicon or germanium to improve
the conductivity of the
semiconductor material.
dot convention
Standard used with transformer
symbols to indicate whether the
secondary voltage is in phase or
out of phase with the primary
voltage.
drift
A problem that can develop in
tuned amplifiers when the
frequency of the tuned circuit
changes due to temperature or
component aging.
dropping resistor
Resistor whose value has been
chosen to drop or develop a
given voltage.
dry cell
DC voltage generating chemical
cell using a non liquid (paste)
electrolyte.
dual in-line package
Integrated circuit package
having two rows of connecting
pins.
dual trace oscilloscope
Oscilloscope that can
simultaneously display two
signals.
dynamic
Relating to conditions that are
changing or in motion
