Author Topic: New EEVBlog Meter, old meter, and scope - all give different readings?  (Read 1607 times)

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Offline .frank.

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No clue what's going on here - maybe someone can watch this video and throw a dog a bone
New eevblog meter gives one voltage, old meter gives another, and scope gives yet a 3rd.

Right click and SAVE this video, don't try and stream it.
http://cia.spacetechnology.net/blog/my-question/question.mp4
 

Offline German_EE

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"A man who has a clock knows the time, a man who has two clocks is never sure"

Segal's Law

The two meters have a different response to the 23 KHz signal riding on the top of the DC so your DC measurements may therefore be different. I also suspect that the EEVBlog meter cannot measure a 23 KHz signal on AC which is why your AC measurements are so weird.

As for your changes in current drawn, the meters provide a capacitive load across a 23 KHz signal.

The correct reading is the one provided by the scope.
Should you find yourself in a chronically leaking boat, energy devoted to changing vessels is likely to be more productive than energy devoted to patching leaks.

Warren Buffett
 

Offline Fungus

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What he said. ^

As soon as you get high frequencies then forget the multimeter. Even the great Fluke 87 can only measure up to 5kHz at those voltages.

The oscilloscope is the one giving the correct voltage reading.

The current draw? Even a slight load on the output could drastically change the efficiency.
 
 

Offline .frank.

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Re: New EEVBlog Meter, old meter, and scope - all give different readings?
« Reply #3 on: August 10, 2016, 02:34:44 am »
Sorry for the late reply.  You guys were correct.  The multi-meter just cant handle that frequency range (neither of them) - scope was right!
 


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