Metal can be protected from corrosion by placing it in contact with a more easily corroded metal. The metal to be protected will act as a cathode and the more easily corroded metal will act as an anode.
In 1920, the memorably named Philo T. Farnsworth conceived the cathode ray vacuum tube used in most all twentieth-century TV sets.
John Green -- An Abundance of Katherines
They had two battered cathode-ray-tube monitors scavenged from a dusty school district storeroom and four videogame joysticks from Radio Shack.
Joshua Davis -- Spare Parts
It would have been a thirteen-inch one, specially made for us wards of the state by Zenith, with a clear plastic shell around its guts and cathodes, so that the COs would be able to tell if you were extracting parts to make weapons.
Jodi Picoult -- Change of Heart
The instrument panel is dominated by six of the largest cathode-ray tubes made, for the display of data.
Dean Koontz -- Sole Survivor
I’ll give him the good Normal world where we’re tethered beside them—blinking our nights away in a non-stop drench of cathode-ray over our shrivelling heads!
Peter Shaffer -- Equus
All this can be measured, at least relatively: a cathode in the brain can register the degree of psychoelectric charge an individual gets from any given sensation—A440 extended to thirty seconds, for example.