The de Broglie wave, or probability amplitude wave (amount by which a voltage or current changes from zero or an average value), associated with an electron.

A function of the spin orientation and position of one or more electrons, specifying the dynamical state of the electrons.

The square of the function's modulus gives the probability per unit volume of finding electrons at a given position.

1. An electron tube which has mutually interacting streams of electrons with different velocities that cause a signal modulation to change progressively along the length of the electron streams.
2. An electron tube in which stream of electrons having different velocities interact and cause a progressive change in signal modulation along their length.