Timeline for Arduino complete self shutdown
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Mar 9, 2017 at 12:12 | comment | added | Milos | I just realized that I didn't knew that current flows from source towards drain in P-type MOSFET, not the opposite, thank you! :) | |
| Mar 9, 2017 at 11:09 | vote | accept | Milos | ||
| Mar 9, 2017 at 11:03 | comment | added | Andrew | It will only conduct in one direction, it works fine as a switch in the other direction. This is a physical limitation due to the internal structure of the parts, just about every modern digital IC manages to work within this limitation so it can't be much of a problem. If you need to switch off without knowing which direction the voltage is higher (a fairly rare situation, normally something like to protect a battery from both over charge and over discharge) then the standard trick is to use two FETs in series with the body diodes in opposite directions. | |
| Mar 9, 2017 at 10:36 | comment | added | Milos | Oh dude my electronic knowledge is so limited! But I still don't get it, if the FET is going to nicely conduct current from drain to source even if voltage between gate and source is ZERO, what is the point of FET? | |
| Mar 9, 2017 at 8:50 | comment | added | Andrew | Through the body diode of the FET. That diode in the first image isn't there to look pretty, it's in all FETs and must be taken into account. Some versions of the symbol don't include it, that's not because it's not there, it because it's always there and they are assuming you know that if you are using the parts. | |
| Mar 9, 2017 at 8:22 | comment | added | Milos | I am sorry, the first image does show a Zener diode packed within MOSFET but it is just a pretty Fritzing image. The second image is an actual screenshot of Multisim and I am wondering how does it measure current if MOSFET has not been triggered at all?! | |
| Mar 8, 2017 at 14:09 | comment | added | Andrew | Oops. Fixed it. | |
| Mar 8, 2017 at 14:08 | history | edited | Andrew | CC BY-SA 3.0 |
added 152 characters in body
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| Mar 8, 2017 at 13:26 | comment | added | Tut | Your first sentence is wrong. The conduction is due to the body diode and cannot be turned off by a negative voltage on the gate which would turn a P-channel MOSFET on, not off. | |
| Mar 8, 2017 at 13:06 | history | answered | Andrew | CC BY-SA 3.0 |