photoelectric cell

GC: n

CT: Photoelectric cell or photocell, device whose electrical characteristics (e.g., current, voltage, or resistance) vary when light is incident upon it. The most common type consists of two electrodes separated by a light-sensitive semiconductor material. A battery or other voltage source connected to the electrodes sets up a current even in the absence of light; when light strikes the semiconductor section of the photocell, the current in the circuit increases by an amount proportional to the intensity of the light. In the phototube, an older type of photocell, two electrodes are enclosed in a glass tube—an anode and a light-sensitive cathode, i.e., a metal that emits electrons in accordance with the photoelectric effect.

S: (last access: 18 December 2014)

N: 1. photoelectric (adj): From photo- (word-forming element meaning “light” or “photographic” or “photoelectric,” from Greek photo-, comb. form of phos (genitive photos) “light,” from PIE root bha- “to shine”) and electric (1640s, first used in English by physician Sir Thomas Browne (1605-1682), apparently coined as Modern Latin electricus (literally “resembling amber”), from Latin electrum “amber,” from Greek elektron “amber”; of unknown origin. In many modern instances, the word is short for electrical).
cell (n): early 12c., “small monastery, subordinate monastery” (from Medieval Latin in this sense), later “small room for a monk or a nun in a monastic establishment; a hermit’s dwelling” (c.1300), from Latin cella “small room, store room, hut,” related to Latin celare “to hide, conceal.”
The Latin word represents PIE root kel- “to cover, conceal”.
Electric battery sense is from 1828, based on original form.
2. Photoelectric cell, also called Electric Eye, Photocell, or Phototube, an electron tube with a photosensitive cathode that emits electrons when illuminated and an anode for collecting the emitted electrons. Various cathode materials are sensitive to specific spectral regions, such as ultraviolet, infrared, or visible light. The voltage between the anode and cathode causes no current in darkness because no electrons are emitted, but illumination excites electrons that are attracted to the anode, producing current proportional to the intensity of the illumination.
3. Mention of the qualifier “solid-state” in this definition implies that phototubes are excluded from it. The Modern Dictionary of Electronics (Rudolf F. Graf, 5th ed. 1977) states that “the term should not be used for a phototube, which is a vacuum tube and not a cell”. However, these terms are, in fact, often used in a more general sense to designate all types of light-sensitive electronic devices. This record deals with the terms in their more restricted sense.

S: 1. OED – (last access: 18 December 2014); (last access: 18 December 2014). 2. EncBrit – (last access: 18 December 2014). 3. TERMIUM PLUS (last access: 18 December 2014).

SYN: electric eye, photocell, phototube.

S: EncBrit – (last access: 18 December 2014)

CR: photoelectric effect, photovoltaic cell.