unidirectional

Moving or operating in one direction only.

Having, or moving in, only one direction; not subject to reversals or changes of direction: said of a direct electric current, or sometimes of a magnetic field of which the lines of force are fixed as to direction.

In electricity, noting currents which flow in the same direction round a circuit.

Pertaining to only one direction, e.g.: where all component parts are aligned in the same direction in space.

operating or moving or allowing movement in one direction only