EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: gkmaia on July 03, 2019, 04:22:08 am
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Just trying to figure out if that is normal for a high voltage diode. Or if this diode is shot.
Its forward bias is at ~5v. There is an image I made of it on my curve tracer.
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If it's a diode rated to several kV, that's normal. I suspect there are internally many well matched diodes in series and/or the semiconductor material used has a wider bandgap. (Maybe someone who actually knows what's inside one can elaborate.)
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This ancient diode will have terrible parameters
That datasheet say 22V @ 5mA
So you must measure on so much higher voltages
If I look at more modern BY8 it have 8V @ 500mA
And even HV SiC diodes start to conduct at 3-4V range
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What is your test current and frequency?
HV rectifier diodes seem to be (roughly) a series stack of 500 PIV diodes. So an 8kV part roughly has Vf about 16V at a few mA.
Y10GA 6kV 5mA Vf=22V max. is pretty much the same as 2CL70 (http://e-edi.com/pdf/diodes/2CL69-77.PDF) Vf=23V at 10mA, fast recovery.
If you are applying only 5-10V, I would think it's only leakage current you should see and a sharper knee above that.
The BY8 does better (lower Vf) I think it's a slow rectifier diode, for microwave ovens?
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Here is nice Forward (and reverse) characteristics of fast HV diode for CRT (8kV one)
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Thanks guys, that was super helpful.