Irfp 240 !!!!!!!!!! - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th January 2003, 11:28 PM   #1
diyAudio Member
 
Join Date: Oct 2002
Location: France
Default Irfp 240 !!!!!!!!!!

Hello touti

I would like to test IRFP 240 effectively,
to know if some did not die
how to have a precise measurement?
__________________
stay zen
  Reply With Quote
Old 9th January 2003, 11:34 PM   #2
diyAudio Member
 
Join Date: Mar 2002
Location: CROATIA
Hello,

This testing procedure is for use with a digital multimeter in the diode test-range with a minimum of 3.3 volt over d.u.t. (diode-under-test).

Connect the 'Source' of the MosFet to the meter's negative (-) lead.

1) Hold the MosFet by the case or the tab but don't touch the metal parts of the test probes with any of the other MosFet's terminals until needed.

2) First, touch the meter positive lead onto the MosFet's 'Gate'.

3) Now move the positve probe to the 'Drain'. You should get a 'low' reading. The MosFet's internal capacitance on the gate has now been charged up by the meter and the device is 'turned-on'.

4) With the meter positive still connected to the drain, touch a finger between source and gate (and drain if you like, it does not matter at this stage). The gate will be discharged through your finger and the meter reding should go high, indicating a non-conductive device.

Such a simple test is not 100% -- but is useful and usually adequate.

When MOSFETS fail they often go short-circuit drain-to-gate. This can put the drain voltage back onto the gate where ofcourse it feeds (via the gate resistors) into the drive circuitry, prossibly blowing that section. It will also get to any other paralleled MosFet gates, blowing them also.
So, if the MosFets are deceased, check the drivers as well! This fact is probably the best reason for adding a source-gate zener diode; zeners fail short circuit and a properly connected zener can limit the damage in a failure! You can also add subminiature gate resistors -- which tend to fail open-circuit (like a fuse) under this overload, disconnecting the MosFet's gate.

Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip
Attached Images
File Type: gif mostest.gif (6.8 KB, 1138 views)
  Reply With Quote
Old 9th January 2003, 11:50 PM   #3
diyAudio Member
 
Join Date: Oct 2002
Location: France
thank you for the explanation for measurements irfp 240
I try to build a aleph 2.
I wanted to know if it was necessary to put 2 inductors of 3.9mh. one for -
one for +

I use 4 X 33000 uf 63 v if it's the case can - you to tell me which inductor I have to use precisely?

escuse my english !!!!!!!!!!!
__________________
stay zen
  Reply With Quote
Old 9th January 2003, 11:53 PM   #4
halojoy is offline halojoy  Sweden
On Hiatus
 
Join Date: Nov 2002
Thumbs up Nice Site you have - with PCB-service

kristijan-k
Nice site you have - http://web.vip.hr/pcb-design.vip/

With great information for Pass-builders.
Plus PCB-service for the projects.

Perfect resource for Pass DIY-selvers!

halojoy - checking the members homepages
Attached Images
File Type: jpg pic-26.jpg (58.8 KB, 1139 views)
  Reply With Quote
Old 10th January 2003, 12:22 AM   #5
Warp Engineer
On Holiday
 
AudioFreak's Avatar
 
Join Date: Oct 2001
Location: Queensland, Australia
I wouldn't particularly advise that you use the method described by kristijan-k. You can use the Vgs matching procedure shown at www.passdiy.com that will not only tell you if the devices are working, but you can also match them at the same time.
  Reply With Quote
Old 11th November 2003, 05:00 PM   #6
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default more expansive article on testing MOSFETs

at PASSDIY - "Practical MOSFET Testing for Audio"
http://www.passdiy.com/pdf/mos.pdf
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
new irfp mosfets elviukai Pass Labs 17 16th March 2007 08:54 AM
IRFP 240 for sale dhole Swap Meet 8 20th July 2005 01:24 PM
irfp Substitute Ipanema Parts 1 13th January 2005 01:29 PM
Yor Opinion on this MOS-Amp (+-80V IRFP[9]240) tab30 Solid State 7 1st December 2003 12:27 PM
irf 240 or irfp 240 for the aleph scu Pass Labs 2 14th January 2002 06:49 PM


New To Site? Need Help?

All times are GMT. The time now is 11:58 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2