Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Simplistic Mosfet HV Shunt Regs
Simplistic Mosfet HV Shunt Regs
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 21st May 2012, 02:24 PM   #3031
albertli is offline albertli  Canada
diyAudio Member
 
albertli's Avatar
 
Join Date: Nov 2004
Location: Vancouver
Quote:
Originally Posted by regal View Post
try replacing the mpsa92
This is what I have but without D1
Attached Images
File Type: gif with protection zener.gif (8.2 KB, 384 views)
  Reply With Quote
Old 21st May 2012, 02:41 PM   #3032
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic Mosfet HV Shunt Regs
Was MJE350 getting particularly hot for long periods before the excess drift appeared recently? Does it have some sort of sinking?
Is the 170 in hot environment? Provide it with some heat relief. A little foil or special TO-92 sink. If you will blow over the 170 while watching Vout you will know.
  Reply With Quote
Old 22nd May 2012, 06:43 AM   #3033
albertli is offline albertli  Canada
diyAudio Member
 
albertli's Avatar
 
Join Date: Nov 2004
Location: Vancouver
Quote:
Originally Posted by Salas View Post
Was MJE350 getting particularly hot for long periods before the excess drift appeared recently? Does it have some sort of sinking?
Is the 170 in hot environment? Provide it with some heat relief. A little foil or special TO-92 sink. If you will blow over the 170 while watching Vout you will know.
My mistake not checking the temperature on the 350, but now they're all new. I didn't put any sink onto them, I'll try doing this if it's necessary. No sink for 170 either.
  Reply With Quote
Old 22nd May 2012, 10:33 AM   #3034
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
The k170 has just 0.6V across it. It dissipates ~4mW. It never gets warm. It does not need a sink.
__________________
regards Andrew T.
  Reply With Quote
Old 22nd May 2012, 11:23 AM   #3035
regal is offline regal  United States
diyAudio Member
 
Join Date: Jan 2004
Location: MD
Quote:
Originally Posted by albertli View Post
This is what I have but without D1
I blew up an MJE that gave symptoms similiar to yours
  Reply With Quote
Old 22nd May 2012, 11:31 AM   #3036
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic Mosfet HV Shunt Regs
Quote:
Originally Posted by AndrewT View Post
The k170 has just 0.6V across it. It dissipates ~4mW. It never gets warm. It does not need a sink.
Not for that. To increase its thermal mass and keep it steadier to ambient. If its drifting so much due to K170 and ambient temp reasons in that build, of course.
  Reply With Quote
Old 22nd May 2012, 11:38 AM   #3037
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
If the temperature inside the case varies, then adding a sink to the jFET will drag the jFET Tc & Tj along with the varying Ta. It will make tempco worse not better.

However, the temperature inside the case should be reasonably stable. This will allow the jFET to hold it's own temperature ~ 1Cdegree above Ta.
__________________
regards Andrew T.
  Reply With Quote
Old 22nd May 2012, 12:29 PM   #3038
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic Mosfet HV Shunt Regs
Don't know, if the temp rise is the case maybe a BF245A lowest IDSS possible from a bunch or 2SK117GR could be steadier. But it has to be checked that the JFET is the one so much affected in that build.
  Reply With Quote
Old 22nd May 2012, 02:11 PM   #3039
albertli is offline albertli  Canada
diyAudio Member
 
albertli's Avatar
 
Join Date: Nov 2004
Location: Vancouver
Since I have the 840 & 350 replaced, does it mean it's a good idea to replace the 170 so to check ?
  Reply With Quote
Old 22nd May 2012, 04:51 PM   #3040
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Simplistic Mosfet HV Shunt Regs
Yes.
  Reply With Quote

Reply


Simplistic Mosfet HV Shunt RegsHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Regs - Shunt vs Series richie00boy Solid State 59 17th June 2017 03:59 PM


New To Site? Need Help?

All times are GMT. The time now is 08:39 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki