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My Mastercraft multimeter.
I bought this multimeter a while ago at Canadian Tire. I waited 'till it gets in clearance. Instead of 59,95C$ I got it for 23,95C$!

Since I bought it I never had any problems, and it still runs with the same half-discharged 9-volt battery! XD

On the pic the device was measuring the resistance of a 40W incandescent lamp. I also lit the backlighting, just for the pic LOL.
Keywords: Miscellaneous

My Mastercraft multimeter.

I bought this multimeter a while ago at Canadian Tire. I waited 'till it gets in clearance. Instead of 59,95C$ I got it for 23,95C$!

Since I bought it I never had any problems, and it still runs with the same half-discharged 9-volt battery! XD

On the pic the device was measuring the resistance of a 40W incandescent lamp. I also lit the backlighting, just for the pic LOL.

DSCN5375.JPG CIMG3351.JPG HPIM4179.JPG HPIM1355.JPG HPIM4245c.jpg
File information
Filename:HPIM4179.JPG
Album name:Vince / Miscellaneous
Keywords:Miscellaneous
Company and Date Manufactured:Mastercraft
Filesize:556 KiB
Date added:Jan 08, 2011
Dimensions:2576 x 1920 pixels
Displayed:116 times
Color Space:sRGB
Contrast:0
DateTime Original:2009:02:14 16:37:37
Exposure Bias:0 EV
Exposure Mode:0
Exposure Program:Program
Exposure Time:37/769 sec
FNumber:f/2.8
Flash:No Flash
Focal length:6 mm
ISO:200
Light Source:Fluorescent
Make:Hewlett-packard
Max Aperture:f/2.8
Model:Photosmart M425
URL:http://www.galleryoflights.org/mb/gallery/displayimage.php?pid=4589
Favorites:Add to Favorites

Comment 1 to 6 of 6
Page: 1

Silverliner14B   [Jan 08, 2011 at 02:38 AM]
24.6 ohms translates into roughly 39.02w at 120v. Pretty much right on the mark Wink
SeanB~1   [Jan 08, 2011 at 06:23 AM]
More like 500W dissipation at switch on, roughly 4.87A inrush current, as opposed to the nominal 0.33A running current. Hot resistance should be around 360 ohms.
Medved   [Jan 08, 2011 at 08:36 AM]
@Silverliner: For my curiosity: How did you come to the 39.02W number?
Silverliner14B   [Jan 08, 2011 at 09:37 AM]
Hot resistance is appromixately 15-16 times of cold resistance. An interesting fact about incandescent lamps, in my experience measuring current during operation and measuring cold resistance, most incandescent lamps consume just below the rated wattage. Some bulbs, especially Chinese junk, rated well below the rated wattage. If it measures above rated wattage its probably overdriven a little.
Medved   [Jan 08, 2011 at 01:45 PM]
The real wattage is below the rated one, as it was rather common to rate incandescent to the maximum side of the mains tolerance range, so they mostly operate below their rating.
But it seems, then this approach changed in last ~10 years at east in Europe, as new bulbs were rated at 230V, so the mains nominal. And my experience is, then they are pretty accurate in the real wattage input here, standard deviation way better then 1%...
MercuryVapor175   [May 14, 2012 at 09:37 PM]
I used a lab power supply, and I powered up some lamps just to prove that a hot resistance is lower, known as the baretter effect. That's also how SBMV filament works.

Comment 1 to 6 of 6
Page: 1