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

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

measuring current load
measuring current load
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
Thread Tools Search this Thread
Old 23rd April 2007, 02:50 PM   #1
jarthel is offline jarthel  Australia
diyAudio Member
Join Date: Jan 2002
Location: somewhere in Australia
Default measuring current load

I know that VOM these days can measure current.

BUT can i use this alternative method to measure current?

for example:

I need to know the current load of a circuit. So I place a 10ohm 50W resistor between the positive lead of the power supply and the circuit. I then measure the voltage drop across the resistor and use ohm's law to determine current.

OR maybe using the VOM's current reading feature still more accurate?

thank you for the help
  Reply With Quote
Old 23rd April 2007, 10:33 PM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
the voltage measuring scales in most multi-meters are more accurate than the resistance and current scales.

If your equipment can tolerate the slight voltage drop from an in-line resistor then voltage loss across the resistor is a good way to measure current. (it's what happens inside a multi-meter).

The resistance you can use can be quite low value and usually does not need to be high wattage. A 1r0 600mW can pass 770mA.
If this were fitted inside a mains fuse, one can with care measure upto 70W on mains equipment. The voltage reading at full current would be just 770mVac so the 2000mVac scale would be appropriate.
BUT TAKE REAL CARE THAT THERE ARE NO DISTRACTIONS, kids/animals/wife/husband around.
regards Andrew T.
  Reply With Quote


measuring current loadHide 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
measuring current using 1ohm resistor. How? riotubes Parts 29 12th April 2009 01:45 AM
Measuring current distortion mashaffer Tubes / Valves 0 25th September 2008 10:37 AM
Measuring Cathode Current Rob11966 Tubes / Valves 7 1st October 2007 11:44 AM
Measuring current with an LCD meter Matttcattt Parts 10 12th May 2004 12:13 AM
Measuring Current Output of an Amp Drew Solid State 10 28th October 2003 04:26 AM

New To Site? Need Help?

All times are GMT. The time now is 11:38 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio