- directional relay
- directive
- directivity
- disadvantage factor
- disappearing filament pyrometer
- disbalance
- disc
- disc coil
- disc winding
- discharge
- discharge capacity
- discharge coil
- discharge column
- discharge counter
- discharge current
- discharge curve
- discharge energy
- discharge gap
- discharge inception voltage
- discharge indicator
- discharge ionization voltage
- discharge lamp
- discharge path
- discharge potential
- discharge resistance
- discharge switch
- discharge tube
- discharge tube rectifier
- discharge voltage
- discharge voltage current characteristic
- discharge voltage time curve
- discharger
- discharging circuit
- discharging gap
- discharging resistor
- disconnecting electromagnet
- disconnecting mechanism
- disconnecting switch
- disconnection
- discontinuous action
- discontinuous control
- discontinuous running
- discontinuous spectrum
- discontinuous system
- discrete absorption
- discrete component
- discrete distribution
- discrete filter
- discrete information
- discrete input action