Register to reply

MOSFET symbol

by antonantal
Tags: mosfet, symbol
Share this thread:
antonantal
#1
Aug21-06, 10:52 AM
P: 219
What does the arrow in the symbol of the MOSFET indicate? I skipped the lecture when we were told this and I can't figure out myself. I mean if it were after me, I would have put that arrow to indicate the direction of the electric field, but the arrow actually points the oposite way. So what does that arrow actually stand for?
Phys.Org News Partner Engineering news on Phys.org
Researchers find security flaws in backscatter X-ray scanners
Virtual reality guides those whose memory is failing
Intelligent navigation system to personalise shopping trips
Maxwell
#2
Aug21-06, 01:58 PM
P: 531
It denotes if the MOSFET is a PMOS or an NMOS.
antonantal
#3
Aug21-06, 02:08 PM
P: 219
Quote Quote by Maxwell
It denotes if the MOSFET is a PMOS or an NMOS.
That's not what I meant. For example in the case of a BJT the arrow indicates the direction of the emitter current in forward active regime. In the case of MOSFET what does it indicate?

dlgoff
#4
Aug21-06, 04:55 PM
Sci Advisor
PF Gold
dlgoff's Avatar
P: 2,719
MOSFET symbol

As Maxwell stated. Either P-channel or N- channel. See this Link.

Regards
antonantal
#5
Aug21-06, 06:12 PM
P: 219
Quote Quote by dlgoff
As Maxwell stated. Either P-channel or N- channel. See this Link.
Again that's not what I'm asking.
Maybe I should put it this way: why is the arrow at the NMOS symbol directed towards the gate and the arrow at the PMOS directed away from the gate?
It must be an analogy with the direction of something. Like in the case of a BJT, the direction of the arrows for npn and pnp are put in analogy with the direction of the emitter current in forward active regime.
chroot
#6
Aug21-06, 06:44 PM
Emeritus
Sci Advisor
PF Gold
chroot's Avatar
P: 10,427
Like electric field lines, arrows are conventionally drawn to point from P to N.

- Warren
antonantal
#7
Aug21-06, 08:23 PM
P: 219
Quote Quote by chroot
Like electric field lines, arrows are conventionally drawn to point from P to N.
So what you mean is that, say for PMOS the arrow points from the channel (P region) towards the rest of the bulk (N region) in analogy with the direction of the electric field between this two regions of the bulk, which is exactly the opposite direction of the electric field initially applied between the gate and the bulk (ie the voltage between gate and bulk)?
Manchot
#8
Aug21-06, 09:01 PM
P: 728
Well, in the abbreviated MOSFET symbols (where the body is assumed to be shorted to the source and isn't shown), the arrow indicates the direction of normal current flow in the device.
antonantal
#9
Aug22-06, 05:50 AM
P: 219
Ok. Thanks for the help guys.
Slayer26M
#10
Sep2-06, 03:06 AM
P: 10
Hole flow and electron flow??


Register to reply

Related Discussions
Self-Switching MOSFET Electrical Engineering 4
MOSFET help Electrical Engineering 2
How to determine transconductance parameter Introductory Physics Homework 0
P-mosfet Transistor Electrical Engineering 0
Question about MOSFET Electrical Engineering 0