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MOSFET
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== Circuit symbols == A variety of symbols are used for the MOSFET. The basic design is generally a line for the channel with the source and drain leaving it at right angles and then bending back at right angles into the same direction as the channel. Sometimes three line segments are used for [[Channel (transistor)|enhancement mode]] and a solid line for depletion mode (see [[depletion and enhancement modes]]). Another line is drawn parallel to the channel for the gate. The ''bulk'' or ''body'' connection, if shown, is shown connected to the back of the channel with an arrow indicating pMOS or nMOS. Arrows always point from P to N, so an NMOS (N-channel in P-well or P-substrate) has the arrow pointing in (from the bulk to the channel). If the bulk is connected to the source (as is generally the case with discrete devices) it is sometimes angled to meet the source leaving the transistor. If the bulk is not shown (as is often the case in IC design as they are generally common bulk) an inversion symbol is sometimes used to indicate PMOS, alternatively an arrow on the source may be used in the same way as for bipolar transistors (out for nMOS, in for pMOS). Comparison of enhancement-mode and depletion-mode MOSFET symbols, along with [[JFET]] symbols. The orientation of the symbols, (most significantly the position of source relative to drain) is such that more positive voltages appear higher on the page than less positive voltages, implying [[Electric current#Conventional current|conventional current]] flowing "down" the page:<ref>{{cite web|archive-url=https://web.archive.org/web/20141013185140/http://www.circuitstoday.com/electronic-circuit-symbols|archive-date=13 October 2014|url= http://www.circuitstoday.com/electronic-circuit-symbols|title=Electronic Circuit Symbols|website=circuitstoday.com|date=9 November 2011}}</ref><ref>{{citation|title=IEEE Std 315-1975 β Graphic Symbols for Electrical and Electronics Diagrams (Including Reference Designation Letters)}}</ref><ref>{{cite book|url=http://highered.mcgraw-hill.com/sites/dl/free/0073191639/366537/Chapter_4.pdf#page=19 |archive-url=https://ghostarchive.org/archive/20221009/http://highered.mcgraw-hill.com/sites/dl/free/0073191639/366537/Chapter_4.pdf#page=19 |archive-date=2022-10-09 |url-status=live|title=Microelectronic Circuit Design|first1=Richard C.|last1=Jaeger|first2=Travis N.|last2=Blalock|chapter=Figure 4.15 IEEE Standard MOS transistor circuit symbols}}</ref> {| class="wikitable" style="text-align:center;" |- ! P-channel | [[file:JFET P-Channel Labelled.svg|80px|class=skin-invert-image]] | [[file:IGFET P-Ch Enh Labelled.svg|80px|class=skin-invert-image]] | [[file:IGFET P-Ch Enh Labelled simplified.svg|80px|class=skin-invert-image]] | [[file:Mosfet P-Ch Sedra.svg|80px|class=skin-invert-image]] | [[file:IGFET P-Ch Dep Labelled.svg|80px|class=skin-invert-image]] |- ! N-channel | [[file:JFET N-Channel Labelled.svg|80px|class=skin-invert-image]] | [[file:IGFET N-Ch Enh Labelled.svg|80px|class=skin-invert-image]] | [[file:IGFET N-Ch Enh Labelled simplified.svg|80px|class=skin-invert-image]] | [[file:Mosfet N-Ch Sedra.svg|80px|class=skin-invert-image]] | [[file:IGFET N-Ch Dep Labelled.svg|80px|class=skin-invert-image]] |- ! ! JFET ! MOSFET {{abbr|enh.|enhancement mode}} ! colspan="2"| MOSFET {{abbr|enh.|enhancement mode}} (no bulk) ! MOSFET {{abbr|dep.|depletion mode}} |} In schematics where G, S, D are not labeled, the detailed features of the symbol indicate which terminal is source and which is drain. For enhancement-mode and depletion-mode MOSFET symbols (in columns two and five), the source terminal is the one connected to the triangle. Additionally, in this diagram, the gate is shown as an "L" shape, whose input leg is closer to S than D, also indicating which is which. However, these symbols are often drawn with a T-shaped gate (as elsewhere on this page), so it is the triangle which must be relied upon to indicate the source terminal. For the symbols in which the bulk, or body, terminal is shown, it is here shown internally connected to the source (i.e., the black triangles in the diagrams in columns 2 and 5). This is a typical configuration, but by no means the only important configuration. In general, the MOSFET is a four-terminal device, and in integrated circuits many of the MOSFETs share a body connection, not necessarily connected to the source terminals of all the transistors.
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