Damping ratio – Damping – Darlington transistor – Darmstadt University of Technology – Data compression – Data networks – DC injection braking – DC-to-DC converter – Decision tree – Deformation (mechanics) – Delay line (disambiguation) – Delco Electronics – Delta-wye transformer – Demand factor – Demand response – Demodulation – Describing function – Design – Desktop computer – Detector (radio) – DIAC – Dielectric – Differential (mathematics) – Digital audio broadcasting – Digital circuit – Digital computers – Digital control – Digital Equipment Corporation – Digital filter – Digital image processing – Digital micromirror device – Digital protective relay – Digital signal controller – Digital signal processing – Digital television – Digital-to-analog converter – Diode bridge – Diode – Direct current – Direct on line starter-- Direct torque control – Discrete cosine transform – Discrete Fourier transform – Discrete signal – Displacement current – Display device – Dissipation – Dissolved gas analysis – Distributed Control System – Distributed element model – Distributed generation – Distribution board – Distribution transformer – Dolby – Dot convention – Doubly fed electric machine – Downsampling – Dqo transformation – Droop speed control – Dual control theory – Dual loop – Ductility – DVD player – DVD – Dynamic braking – Dynamic demand (electric power) – Dynamic programming – Dynamic random access memory – Dynamic system – Dynamo –