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Why does arrow in N mosfet point towards channel?

B

blackhead

Jan 1, 1970
0
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.
 
B

blackhead

Jan 1, 1970
0
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?

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

Joerg

Jan 1, 1970
0
Jim Thompson wrote:

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

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

<duck and run>
 
J

Joerg

Jan 1, 1970
0
Jim said:
There ya' go ;-)

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

Spehro Pefhany

Jan 1, 1970
0
So electrons are usually blue?

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


Best regards,
Spehro Pefhany
 

neon

Oct 21, 2006
1,325
Joined
Oct 21, 2006
Messages
1,325
Why not it signefy a force fied on the substrate.
 
J

Jasen Betts

Jan 1, 1970
0
Why does the arrow in an N-channel mosfet symbol point towards the
channel from the substrate?

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

Tim Williams

Jan 1, 1970
0
How do you like this symbol? ;-)

http://webpages.charter.net/dawill/Images/Analog_Switch_3.gif

As for MOSFETs, the arrow represents the substrate-channel diode. It always
makes me shake my head when I see those symbols with the parasitic zener
explicitly piggybacked, as though it were an entirely seperate element
(which is isn't, though schottky-backed MOSFETs and FRED-backed IGBTs exist,
but neither is the pure MOSFET we're talking about). It's as if people
don't even know the meaning of the symbol they're using.

Tim
 
J

Joerg

Jan 1, 1970
0
Jim said:
Leftists electrons are always blue... always think they're entitled to
something they haven't yet received.

And that leaves holes everywhere.
 
E

ehsjr

Jan 1, 1970
0
Jim said:
Leftists electrons are always blue... always think they're entitled to
something they haven't yet received.

...Jim Thompson

Isn't there a charge for that?

Ed
 
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