jonnyGURU Forums
Home Site Search Reviews Articles Contest Links PSU FAQs  


Go Back   jonnyGURU Forums > Site and Forum Topics > Testing Methodology Discussion

Testing Methodology Discussion Questions and comments regarding the testing methodologies used on jonnyguru.com

Reply
 
Thread Tools Display Modes
  #1  
Old 07-09-2016
crmaris's Avatar
crmaris crmaris is offline
Cybenetics CTE
 
Join Date: Jan 2010
Location: Greece
Posts: 1,473
Thanks: 145
Thanked 441 Times in 207 Posts
Default New project on the horizon..

In the past I used to have time to start a new project every now then. I really miss these days... Although during this period I am over head with work, I decided to devote some time in a very interesting area that has to do with power measurements, my favorite sport.

Measuring the power consumption of various parts, including VGAs and CPUs is very challenging. For starters there is no way to measure power consumption on a VGA with a plain multimeter since you will lose most of the interesting information (power spikes). You need something much faster. On the other hand, the combination of a scope with hall-effect probes has its own problems. For starters it is a really expensive combination (a good probe easily exceeds 2k and you also need an expensive scope to pair it with). Secondly, hall-effect sensors are prone to magnetic fields and in many cases bandwidth can become an issue.

But and shunt resistors aren't problem free, since in very large currents lots of energy is lost on them hence they seriously affect the circuit. But they are very cheap and provide high accuracy, and in case you want to measure higher currents you can use more than one in parallel, in order to reduce power losses on them.

To be continued, once I find the time...







the multimeters were used only for some basic tests in order to check if everything was connected ok. Afterwards I installed a 4-channel, high-resolution Picoscope. But I was too tired to shoot any photos.
Reply With Quote
The Following 4 Users Say Thank You to crmaris For This Useful Post:
-The_Mask- (07-10-2016), Philipus II (07-09-2016), quest for silence (07-14-2016), sith'ari (07-09-2016)
  #2  
Old 07-09-2016
sith'ari sith'ari is offline
Flux Capacitor User
 
Join Date: Oct 2014
Location: Emperor's Retreat/Naboo Moenia
Posts: 869
Thanks: 1,418
Thanked 205 Times in 126 Posts
Default

Quote:
Originally Posted by crmaris View Post
.................................................. ...................
Measuring the power consumption of various parts, including VGAs and CPUs is very challenging. For starters there is no way to measure power consumption on a VGA with a plain multimeter since you will lose most of the interesting information (power spikes).
I guess that you got this idea after this hole issue with the RX480's excessive power draw from the pci-e slot?
__________________
CPU:Athlon 64 FX60 (2-cores) 2,6GHz
Mobo:Asrock 939a785g
cpu cooler:ArcticFreezer13 CO
RAM:4 GB DDR 400MHz
GPU:Asus 750 Ti 2GB
PSU:Seasonic Platinum 660
Monitor:Asus VE228HR
Tower:Coolermaster Elite 430
Reply With Quote
  #3  
Old 07-09-2016
turkey3_scratch's Avatar
turkey3_scratch turkey3_scratch is offline
was here for PSUs, now for the jokes
 
Join Date: Nov 2015
Location: U.S.A.
Posts: 1,245
Thanks: 295
Thanked 216 Times in 152 Posts
Default

So what exactly are you doing differently than the normal methodologies for measuring power? Are you trying to develop an alternative to scope, shunts, and multimeters, or are you rather utilizing all three and comparing the results?
Reply With Quote
  #4  
Old 07-09-2016
crmaris's Avatar
crmaris crmaris is offline
Cybenetics CTE
 
Join Date: Jan 2010
Location: Greece
Posts: 1,473
Thanks: 145
Thanked 441 Times in 207 Posts
Default

Quote:
Originally Posted by sith'ari View Post
I guess that you got this idea after this hole issue with the RX480's excessive power draw from the pci-e slot?
Nope, I was planning to do this much earlier because of an article that I was assigned to update.
Reply With Quote
  #5  
Old 07-09-2016
crmaris's Avatar
crmaris crmaris is offline
Cybenetics CTE
 
Join Date: Jan 2010
Location: Greece
Posts: 1,473
Thanks: 145
Thanked 441 Times in 207 Posts
Default

Quote:
Originally Posted by turkey3_scratch View Post
So what exactly are you doing differently than the normal methodologies for measuring power? Are you trying to develop an alternative to scope, shunts, and multimeters, or are you rather utilizing all three and comparing the results?
I am simply trying to do it better, with increased accuracy and with 1/10 the cost. Forgot to mention that besides the hardware part I will also code a special application for this which will monitor the scope(s) and the data logging device for the voltage readings. My only problem is time but I am not in a hurry to finish this project since I am enjoying it.
Reply With Quote
  #6  
Old 07-09-2016
-The_Mask-'s Avatar
-The_Mask- -The_Mask- is online now
ssssssmokin'
 
Join Date: Jun 2010
Location: The Netherlands
Posts: 4,619
Thanks: 329
Thanked 1,304 Times in 853 Posts
Default

Quote:
Originally Posted by crmaris View Post
Measuring the power consumption of various parts, including VGAs and CPUs is very challenging. For starters there is no way to measure power consumption on a VGA with a plain multimeter since you will lose most of the interesting information (power spikes).
It gives you of course a lot more information, but where are you gonna use that information for. Better measurement is of course always better, but average numbers are much more interesting for the readers. I believe most readers are only getting more confused with those numbers.

Quote:
Originally Posted by sith'ari View Post
I guess that you got this idea after this hole issue with the RX480's excessive power draw from the pci-e slot?
More a really stupid thing then a real issue and of course already fixed with a driver update.
Reply With Quote
  #7  
Old 07-09-2016
Behemot Behemot is offline
Banned
 
Join Date: Aug 2013
Location: 504'53.169"N, 1423'30.699"E
Posts: 1,578
Thanks: 90
Thanked 249 Times in 183 Posts
Default

Well yeah you can buy very high precision (0.1 %) shunts with low Vdrop (200 or just 60 mV) for example in Germany. They are usually big so no problem with cooling. But they are big so problem with space, and not entirely cheap.

I presume that with combination of such shunt and O-scope you can also see how the power draw behaves on close level (short intervals like sub 1 ms) as you just scope the voltage over the shunt (OFC with differential probe or two probes and some math function). Been thinking about this as well, just thinking for now…
Reply With Quote
Reply

Thread Tools
Display Modes

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


All times are GMT -4. The time now is 03:59 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Copyright © JonnyGURU.com 2000 -