Saturation current

Saturation current

Saturation current is a term used to describe a limit to the amount of current that can flow in an electronic circuit or device. As the voltage applied to a circuit is increased, the current flow will increase proportionately until the saturation current is achieved, at which point the excess current can no longer flow, and is instead converted into heat. This excess heat can cause overheating and even failure if a device's cooling capabilities are inadequate. The physical explanation for current saturation may be a fixed density of charge carriers (electrons) and a maximum possible value for their velocity, and has some conceptual parallels to the notion of mechanical friction.

To better comprehend the notion of current saturation, an analogy can be made to our everyday experience of water flowing through a faucet. As one opens the faucet, the flow of water increases, but only up to a certain maximum amount. That maximum might be described as the faucet's "saturation flow", although such a term is not in use.

One of the most ubiquitous exploits of saturation current is in the incandescent light bulb.

In electronics, the heat generated by attempting to exceed a device's saturation current is leveraged in the design of a fuse, where that excess heat is used to melt a metallic conductor, thereby interrupting the current.

In transistors, velocity saturation usually occurs before the transistor itself goes into saturation. From a design point of view, this means that designed circuits will usually be slower than expected.

See also

* Transistor
* Diode, especially the section on Analysis
* Triode
* Langmuir probe, especially the sections on Ion saturation current density and Electron saturation current
* Debye sheath, especially the section on The Child-Langmuir Law


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • saturation current — soties srovė statusas T sritis automatika atitikmenys: angl. saturation current vok. Sättigungsstrom, m rus. ток насыщения, m pranc. courant de saturation, m …   Automatikos terminų žodynas

  • saturation current — soties srovė statusas T sritis fizika atitikmenys: angl. saturation current vok. Sättigungsstrom, m rus. ток насыщения, m pranc. courant de saturation, m …   Fizikos terminų žodynas

  • saturation current density — soties srovės tankis statusas T sritis fizika atitikmenys: angl. saturation current density vok. Sättigungsstromdichte, f rus. плотность тока насыщения, f pranc. densité du courant de saturation, f …   Fizikos terminų žodynas

  • saturation current — noun : the limiting current through an ionized gas or an electron tube such that further increase of voltage produces no further increase in current …   Useful english dictionary

  • saturation current — noun the maximum current that can be obtained in a specific circuit under specified conditions …   Wiktionary

  • saturation current — the amount of current in an x ray tube when the voltage is sufficient to drive all the electrons produced from the cathode filament to the anode as fast as they are produced …   Medical dictionary

  • Current mirror — A current mirror is a circuit designed to copy a current through one active device by controlling the current in another active device of a circuit, keeping the output current constant regardless of loading. The current being copied can be, and… …   Wikipedia

  • Saturation (magnetic) — Magnetization curves of 9 ferromagnetic materials, showing saturation. 1.Sheet steel, 2.Silicon steel, 3.Cast steel, 4.Tungsten steel, 5.Magnet steel, 6.Cast iron, 7.Nickel, 8.Cobalt, 9.Magnetite[1] Seen in some magnetic materials, saturation is… …   Wikipedia

  • Current transformer — A CT for operation on a 110 kV grid In electrical engineering, a current transformer (CT) is used for measurement of electric currents. Current transformers, together with voltage transformers (VT) (potential transformers (PT)), are known as …   Wikipedia

  • Current–voltage characteristic — Figure 1. I–V curve of a P–N junction diode (not to scale). A current–voltage characteristic is a relationship, typically represented as a chart or graph, between an electric current and a corresponding voltage, or potential difference. In… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”