- dead contact
- deadman
- deflection sensitivity
- deflection Yoke
- degree
- delay cable
- delayed AGC
- deliver
- delivery conduit
- delivery time
- delta connected
- delta connection
- delta network
- delta voltage
- delta-delta
- delta-star
- demagnetisation curve
- demand
- decalescent point
- decay characteristic
- decoupling
- deflection coil
- deformation
- defrosting cycle
- decay factor
- decay time
- deflection
- demand meter
- demodulator
- density gauge
- department head
- despiking circuit
- detector
- detector crystal
- deviation ratio
- department store
- dephase
- depletion layer
- deposition
- dichromate cell
- dictionary
- dielectric fatigue
- dielectric loss
- dielectric strength
- diesel
- diesel oil
- difference
- differential
- differential magnetometer
- differential relay
- design
- design technology
- developing fault
- diac
- diamagnetism
- diaphragm
- dielectric constant
- dielectric test
- dielectric wedge
- differential synchro
- differential thermocouple
- digit
- dim
- dimmer switch
- diode thyristor
- dip
- DIP relay
- dipheser
- derived current
- desiccator
- destination
- determination
- deuterium
- dewater
- dial lamp
- dial plate
- diamagnetic material
- diamond winding
- dipole layer
- direct component
- direct feedback
- direct sequence
- direct suspension
- dielectric breakdown
- dielectric coefficient
- dielectric film
- dielectric hysteresis
- dielectric properties
- dielectric viscosity
- dielectricity
- differential ammeter
- differential voltage
- differential voltmeter
- diffuser
- digit drum
- digital ammeter
- digital computer
- digital meter
- digital relay
- direction switch