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Old 12-17-2019, 04:42 PM   #1
tmhobadcap
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Default Diode testing question

I have a diode that I want to test. The markings on it is 31DQ 06 8C. From the internet, I found that its forward voltage drop is about 0.6V. But when I test it with my multimeter in diode testing mode, the forward voltage drop is only 0.173V. Does this mean the diode is defective? Or is my multimeter not working? Or I got the wrong information on the diode from the internet?

Last edited by tmhobadcap; 12-17-2019 at 04:44 PM..
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Old 12-17-2019, 04:52 PM   #2
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Default Re: Diode testing question

That is a Schottky rectifier diode, it will check with a lower voltage drop. it is good
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Old 12-17-2019, 05:01 PM   #3
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Default Re: Diode testing question

Different types of rectifiers/diodes have different forward drops: silicon vs. germanium vs. silicon carbide; schottky vs. standard recovery vs. (ultra-)fast recovery.
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Old 12-17-2019, 05:03 PM   #4
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Default Re: Diode testing question

The Vf rating is based at 3Apk @25c.
if you look at the graph, the Vf will vary with the If, since your meter cannot put out high forward current so the Vf reading will be lower when you use your meter, see graph on page 3.
http://www.mouser.com/catalog/specsheets/9332031d.pdf
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File Type: pdf 31DQ06.pdf (107.8 KB, 12 views)
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Old 12-17-2019, 05:51 PM   #5
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Default Re: Diode testing question

Thank you for all your replies.
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