- adaptor
- additional error
- additional winding
- adimettance matrix
- adjustable inductance
- adjustable transformer
- adjusting nut
- adjusting resistor
- administered price
- adapter
- adaptive equalization
- adder
- adequate
- adiabaticity
- adiabatism
- adjacent coil
- adjustable capacitor
- adjustable resistor
- adjustable spanner
- adjusting
- admissible error
- admittance
- admittance matrix
- advance
- advance angle
- aerial conductor
- aerial line
- aesthetics
- after glow
- aftercurrent
- aged
- ageing
- ageing test
- air drier
- air gap
- air inductor
- air-dielectric
- air capacitor
- air transformer
- alkali
- alkaline cell
- all-insulated
- allen key
- agonic line
- air breaker
- air brush
- air condenser
- air regulator
- air separator
- alignment
- alignment tool
- alkaline battery
- Allan cell
- allowable length
- alnico
- alpha particle
- alpine zone
- alternating current
- alternating discharge
- alternating load
- alumel
- aluminium conductor
- amalgamated
- amalgamation
- amber color
- ambiguity function
- ammonia machine
- amortisseur
- ampere
- ampere density
- ampere-second
- ampere-turn
- amperemeter
- amperite tube
- amphoteric substance
- amplitude distortion
- amplitude range
- analyzer
- anchor clamp
- anchor plate
- anchor shackle
- ancillary
- angle steel
- anion
- annealed copper
- anode circuit
- answerback
- antenna power
- angstrom
- angular degree
- annunciation
- annunciator relay
- anodal
- anode
- anodic
- anodic etching
- anodising
- anolyte
- answering jack
- amperage