DAC - Abbreviation for "digital to analog converter."
damping - 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 - The 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.
dielectric constant - Property of a material that determines how much electrostatic energy can be stored per unit volume when unit voltage is applied.
dielectric 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.