Why does arrow in N mosfet point towards channel?

Why does the arrow in an N-channel mosfet symbol point towards the channel from the substrate?

Logically, I would have thought that because electrons from the substrate move towards the channel to enhance it which would mean the direction of conventional current flow will be from the channel to the substrate.

cheers.

Reply to
blackhead
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Because the "body" is P-type...

P -> N

Ummmm! Apply some student thought to that idea ;-)

A positive gate voltage (relative to body) does what?

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Mine don't.

| | | | |---- | | ------| | | | |->- | | | |

John

Reply to
John Larkin

That's a crappy symbol, particularly since both drain _and_ source, for an N-channel device, are N-type "plugs".

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

I couldn't care less how the fet is made. I care about visualizing the circuit it appears in. An SCR has four layers... does your schematic symbol show all four somehow?

I "invented" this symbol because it's more intuitive to me, and because it's easier to resolve on B-size schematics. But I have seen it used elsewhere, including in "equivalent" IC schematics on data sheets.

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John

Reply to
John Larkin

How many layers does an NMOS device have ?;-)

An SCR is a doomsday machine in an ASIC ;-)

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Attract minority carriers -- electrons -- from the p-type substrate into the channel under the gate so enhancing it.

=A0 =A0 ...Jim Thompson

=A0 | =A0 =A0mens =A0 =A0 |

=A0 | =A0 =A0 et =A0 =A0 =A0|

=A0|

=A0 =A0 =A0 |

Reply to
blackhead
[...]

And in linear supplies when before the pass device ...

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SCNR, Joerg

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Reply to
Joerg

There ya' go ;-)

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Definitely blows fuse _before_ anything else is stressed.

You'd better ;-)

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Do the minority carriers qualify for affirmative action treatment once they made it over into the channel?

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SCNR, Joerg

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Reply to
Joerg

Yes. They qualify for wealth redistribution ;-)

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

So electrons are usually blue?

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Reply to
Joerg

Leftists electrons are always blue... always think they're entitled to something they haven't yet received.

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

They must be organizers. Remove the electrons and the atoms are no longer unionized.

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

Remove the neutrons and you'll have no managers.

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Reply to
Michael A. Terrell

same reason the arrow in an NPN transistor points towards the emitter.

Reply to
Jasen Betts

Except it doesn't.

John

Reply to
John Larkin

You've obviously never been taught the mnemonic Never Point iN for NPN.

Jim

Reply to
RST Engineering (jw)

The arrow points the way the current (usually) flows.

John

Reply to
John Larkin

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