How spot random PIN diodes?

[throbscottle]

I've been sorting out my board pull smd diode collection (result of looking for a schottky for the ridiculously complicated drill controller). Many possible types for most of the case markings, and a lot have PIN diode listed as a possible type. (I don't know where they came from so that doesn't help). How can I tell if that is what they are?

 

[gophert]

How can I tell if that is what they are?

It's much easier to tell if you order them from Digikey or other authorized distributor and simply read the package.

 

[Nigel Goodwin]

It's much easier to tell if you order them from Digikey or other authorized distributor and simply read the package.

I completely agree, it's a waste of time pulling SMD's as many have no markings at all, and those that do often are impossible to identify what the code means.

 

[throbscottle]

You've both missed the point. I don't actually want to use a PIN diode for anything, it's not something I'm interested in using (well, until I am).

I have an effective system for retrieval (heat and scrape) sorting (mini magnetised triangle trays on a white piece of steel sheet and a small whiteboard marker) storage (labelled small centrifuge tubes grouped in labelled bags, all in lidded container) and identification (bootleg copy of the Turuta SMD codebook + BangGood Hiland component tester + homemade test jig) and retrieval (a spreadsheet which contains lines copied from the codebook of all the possible devices for any one top mark that I actually have). So if I want a particular type of component, I can look at my stock, retrieve R's and C's directly, semiconductors I can just look up the type of device I want in the spreadsheet and test the matching devices to make sure they are actually as expected. Around 95% of devices are identifiable with 95% accuracy.

But diodes are a bit harder because for any top mark there is a greater diversity of candidates for any device. I can still pin it down to one exact diode but it takes more work, and if my requirement is so specific it actually matters then I would just buy it anyway. But usually I want "any switching diode" or "any rectifier over x amps and y volts" or "any schottky diode" or "any zener of x volts", so it doesn't matter, any purchase would be cost based so why pay when my own time is free and I usually get what I want much quicker?

So going back to PIN diodes, the point is, I see a lot of candidates for any diode top mark which include varicap and PIN types. 99% of what I have is ordinary diodes, but supposing I do have an odd PIN diode in there? My curiosity is piqued, what traits do I look for?

 

[Mickster]

This video may help:

 

[gophert]

You've both missed the point.

We may have missed the point but your initial post did not motivate us to stop and aim accurately.

At less than MHz (10s of MHz) frequencies, a PIN Diode looks a lot like a rectifier diode. Do you have RF test equipment.

 

[JimB]

Thank you for that video Mickster.

That guy w2aew does some very good instructional videos, always well presented.
If I remember correctly, he is an applications engineer for Tektronix.

JimB

 

[Mickster]

Here is a list in PDF form, linked to each video:

https://www.qsl.net/w2aew/youtube/W2AEW_video_index.pdf

I will always watch Alan's videos first, if they appear in any search results.

 

[throbscottle]

Ahh, apologies, I will try to motivate your aim in future RF testing is possible for me but it's all very kludgy in the GSF (Garden Shed Facility)

Thanks Mickster for the excellent video. Now I'm a little more motivated to experiment in the world of RF. I guess at the DC level I could look out for that large forward capacitance.

 

[gophert]

Ahh, apologies, I will try to motivate your aim in future

thank you.

I guess at the DC level I could look out for that large forward capacitance.

that DC capacitance is in the range of 1pF or less.

 

[throbscottle]

Doh!
I thought in the video he said they have a lot of forward capacitance and tiny reverse capacitance. I'll have to watch it again.