Author Topic: To whom it may concern: N vs. P channel MOSFETs.  (Read 4308 times)

0 Members and 1 Guest are viewing this topic.

Offline ElectroIrradiator

  • Frequent Contributor
  • **
  • Posts: 614
  • Country: dk
  • More analog than digital.
To whom it may concern: N vs. P channel MOSFETs.
« on: August 04, 2015, 02:04:33 pm »
(Yes, I do believe this is in the right forum section. :D )

Please be adviced that usually you[1] cannot replace an N channel MOSFET with a P channel ditto without suffering some dire consequences. That is why the first replacement MOSFET instantly blew up when you applied power. You shorted out the battery through the body diode, and the current was only limited by the DC resistance of the transformer. ;D

Otherwise enjoyed the video as always. :popcorn:

[1] Message meant for a fairly narrow selection of 'you'.
« Last Edit: August 04, 2015, 02:11:24 pm by ElectroIrradiator »
 

Offline McBryce

  • Super Contributor
  • ***
  • Posts: 2523
  • Country: de
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #1 on: August 04, 2015, 02:11:21 pm »
That's a VERY narrow "you" indeed. Any chance of a link to the video? :)

McBryce.
30 Years making cars more difficult to repair.
 

Offline ElectroIrradiator

  • Frequent Contributor
  • **
  • Posts: 614
  • Country: dk
  • More analog than digital.
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #2 on: August 04, 2015, 02:13:02 pm »
Apparently Shahriar and I were typing our respective posts at the same time.  ;D

Edit: I spelled Mr. S' name incorrectly... :palm:
« Last Edit: August 04, 2015, 02:29:29 pm by ElectroIrradiator »
 

Offline McBryce

  • Super Contributor
  • ***
  • Posts: 2523
  • Country: de
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #3 on: August 04, 2015, 02:20:07 pm »
It wouldn't be a Shahriar video if nothing exploded or caught fire :)

McBryce.
30 Years making cars more difficult to repair.
 

Offline dadler

  • Supporter
  • ****
  • Posts: 851
  • Country: us
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #4 on: August 05, 2015, 02:19:26 am »
I am supremely confident that Shahriar knows the difference between P and N channel mosfets, considering he has a Ph.d in EE and works at Bell Labs (engineering manager, designing microwave-frequency ASICs)--in the building where the transistor was invented.
« Last Edit: August 05, 2015, 02:21:40 am by dadler »
 

Offline ElectroIrradiator

  • Frequent Contributor
  • **
  • Posts: 614
  • Country: dk
  • More analog than digital.
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #5 on: August 05, 2015, 07:55:33 am »
I am supremely confident that Shahriar knows the difference between P and N channel mosfets, considering he has a Ph.d in EE and works at Bell Labs (engineering manager, designing microwave-frequency ASICs)--in the building where the transistor was invented.

I know about his background in general terms.

I am also supremely confident that we all make those :palm: mistakes from time to time.
 

Offline MagicSmoker

  • Super Contributor
  • ***
  • Posts: 1408
  • Country: us
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #6 on: August 05, 2015, 10:53:35 pm »
...I am also supremely confident that we all make those :palm: mistakes from time to time.

Yes, this. I am always impressed when someone with a stellar pedigree does something exceptional stupid but still owns up to it; conversely, I am totally unamused when some wet-behind-the-ears intern blames an incomplete datasheet or the like for his/her failure.

 

Offline dadler

  • Supporter
  • ****
  • Posts: 851
  • Country: us
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #7 on: August 06, 2015, 12:15:02 am »
In this case though, Shahriar just showed the wrong datasheet in the video. The newly-toasted mosfet in question was indeed N channel and actually only rated for 400mA. Hence why the to-220 mosfet was getting super hot, as the dc converter circuit really pulls a lot of current.
 

Offline Hugoneus

  • Frequent Contributor
  • **
  • Posts: 926
  • Country: us
    • The Signal Path Video Blog
Re: To whom it may concern: N vs. P channel MOSFETs.
« Reply #8 on: August 21, 2015, 04:11:00 pm »
I just saw this! :)

In this case I showed the wrong datasheet in the video. As I was searching for replacement parts I downloaded many datasheets in the process. I added a note to the video.

Indeed if a PMOS would be used, it would put the DC-DC converter in positive feedback and would surely destroy the device in question.


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf