Author Topic: Diode Excessive reverse leakage current - Causes?  (Read 954 times)

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Offline JesterTopic starter

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Diode Excessive reverse leakage current - Causes?
« on: April 20, 2020, 05:01:23 pm »
I was troubleshooting a circuit today and tracked it down to excessive reverse leakage current (1n4005 diode).  Checked fine with diode function on DMM, however I suspected it was flaky and found reverse leakage to be about 10uA @ 10V and 30uA@100V at room temperature.


These are probably about 30+ years old. However the device looks like new inside, must have been kept in a clean lab.

Does anyone know the contributing factors that cause this? Age, transients, humidity?


 

Offline David Hess

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Re: Diode Excessive reverse leakage current - Causes?
« Reply #1 on: April 20, 2020, 07:54:00 pm »
It could be all of those things or more likely a defective batch of diodes.
 
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Offline trobbins

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Re: Diode Excessive reverse leakage current - Causes?
« Reply #2 on: April 21, 2020, 12:14:37 am »
Was the part subject to transient risk (eg. mains supply rectifier)?
 
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Offline Neomys Sapiens

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Re: Diode Excessive reverse leakage current - Causes?
« Reply #3 on: April 22, 2020, 01:46:26 am »
For plastic encapsulated diodes, moisture absorbtion would be a major cause for excessive reverse current by leakage, that means going around the semiconductor crystal, rather than through it.
 
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Offline graybeard

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Re: Diode Excessive reverse leakage current - Causes?
« Reply #4 on: April 22, 2020, 03:14:14 am »
Moisture is a real possibility.

You can try to bake it out.  Set your oven for 300F or 150C and put it in overnight.  Then if you measure it again and the leakage has dropped you will know it was moisture.
 
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