phototube
Noun: - A type of electron tube: A "phototube" is an electron tube whose electrical output varies in response to changes in light intensity. It typically contains a photocathode that emits electrons when exposed to light, and an anode that collects these electrons to produce an electric current.
- (A device that changes light into an electric current for transmission.)
- (They adjusted the tube to detect varying light levels precisely.)
- (The tube detects changes in light caused by smoke.)
"Phototube amplifier": A circuit that increases the weak electrical signal from a phototube for practical use.
- The phototube amplifier boosted the current enough to trigger the alarm. (The amplification made the signal strong enough to activate the system.)
"Gas-filled phototube": A type of phototube containing a small amount of gas to enhance sensitivity.
- A gas-filled phototube is more responsive to low light levels than a vacuum type. (The gas improves the tube's ability to detect faint light.)
Photoelectric (adj): relating to the emission of electrons from a material when light strikes it.
- The photoelectric effect is the principle behind the phototube. (The emission of electrons due to light is the basis for its operation.)
Photocathode (n): the electrode in a phototube that emits electrons when illuminated.
- The photocathode is coated with a light-sensitive material. (The surface that releases electrons in response to light.)
Photomultiplier (n): a more advanced device that amplifies the electron signal from a phototube.
- A photomultiplier can detect extremely weak light signals. (It uses multiple stages to increase sensitivity.)
- Light-sensitive tube: a tube that responds to light.
- Photoemissive cell: a cell that emits electrons upon light exposure.