MOSFET Symbol: Meaning of Arrow?

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The arrow in the MOSFET symbol indicates whether the device is a PMOS or NMOS. For NMOS, the arrow points towards the gate, while for PMOS, it points away, reflecting the direction of current flow in relation to the electric field. This convention is analogous to the emitter current direction in BJTs, where arrows indicate current flow. The discussion highlights the relationship between the arrow's direction and the electric field between the P and N regions. Understanding this helps clarify the operational principles of MOSFETs.
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What does the arrow in the symbol of the MOSFET indicate? I skipped the lecture when we were told this :smile: 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?
 
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It denotes if the MOSFET is a PMOS or an NMOS.
 
Maxwell said:
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?
 
As Maxwell stated. Either P-channel or N- channel. See this http://encyclobeamia.solarbotics.net/articles/mosfet.html" .

Regards
 
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dlgoff said:
As Maxwell stated. Either P-channel or N- channel. See this http://encyclobeamia.solarbotics.net/articles/mosfet.html" .

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.
 
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Like electric field lines, arrows are conventionally drawn to point from P to N.

- Warren
 
chroot said:
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)?
 
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.
 
Ok. Thanks for the help guys.
 
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Hole flow and electron flow??
 

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