a method used to recreate an analogue signal that has been coded into binary data and transmitted as a digital signal.

Digital/Analogue Converter (DAC):

a device used to generate a replica of the original analogue signal that has been coded into binary data and transmitted as a digital signal

Direct Current (DC):

A current flow which is steady with time, and flows in one direction only

Distortion (1):

Any modification to a signal which results in the generation of frequencies which were not present in the original

Distortion (2):

Of phase, any modification of the phase relationship between two or more signals which causes the observed waveform to differ from the original

DSP:

Digital Signal Processor - a dedicated computer circuit which performs complex changes or analysis on a digital signal, generally encoded from an analogue source

DAC

Abbreviation for "digital to analog converter."  

 

damping

Reduction in magnitude of oscillation due to energy being dissipated as heat.

  

DC

Abbreviation for "direct current".

 

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.

   

delay time

The time for collector current to reach 10% of its maximum value in a BJT switching circuit.

 

depletion region

There area surrounding a pn junction that is depleted of carriers.    

device

A component or part.

   

dielectric

Insulating material between two plates where an electrostatic field exists.

   

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.

   

dissipation

Release of electrical energy in the form of heat.

 

distortion

An undesired change in a waveform or signal.

   

domain

A moveable magnetized area in a magnetized material. Also known as magnetic domain.

 

doping

The process of adding impurity atoms to intrinsic (pure) silicon or germanium to improve the conductivity of the semiconductor material.

   

drift

A problem that can develop in tuned amplifiers when the frequency of the tuned circuit changes due to temperature or component aging.

   

dry cell

DC voltage generating chemical cell using a non liquid (paste) electrolyte.