Build Your Own Clone Message Board

I purchased a 'Clipping Selector Kit' (https://store.generalguitargadgets.com/ ... 0453140564) from GGG and the kit included pair of, what I
am assuming to be glass diodes, but there are no numbers printed on them. I am attaching a photo of one with a 1N4148 for comparison. Can anyone identify it for me? I sent JD an email via the contact form on his web site, but have not heard back from him as of yet.

Thanks, in advance,
-=SteveO

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“To know, and not to do, is not to know”

It's possible that it's just very generic, you know, it's a diode. Do you have a diode test function on your multimeter? You may be able use that to find out whether it's silicon or germanium, and maybe that's all you need to know. I'm guessing that if it's more exotic then it would have numbering on it.

Thanks for the input! I have an inexpensive component tester and it seems to think it's a 33pF capacitor, and my DMM wasn't much help either.
I guess I'll socket that PCB and do some experimenting.

Thanks again!

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“To know, and not to do, is not to know”

I'd be curious to see what happens if you try your meter again, but with the opposite polarity. I wonder if that's a zener.

Here it is...

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“To know, and not to do, is not to know”

Hmmmmm interesting. Sort of like a 2.7 V zener diode but the forward-bias voltage seems partway between what I would expect for silicon and for germanium. I tried to look up the manual for that DMM and it seems to indicate a diode test current of 0.5 mA, for which I'd expect more like 0.5 or 0.6 V for Si and 0.25 V or so for Ge. It's a stumper ...

I have a bag of 1N34A germaniums from Tayda that look exactly like that, including the internal construction. But they read between .25 - .3V in the forward direction but don't register any reading in the reverse direction, as you would expect from a Ge diode. Have you tried measuring any others of that same type from the assortment you received?

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

There were only two in the kit. The other one reads 0.39v and open (0.0v).

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“To know, and not to do, is not to know”

I'm quite certain those are germaniums. My understanding is that most of them are NOS out of Russia, and I've seen quite a range of forward voltage values, up as high as 0.7V (which is silicon diode territory). You can compare their construction to the super-enlarged photo below, and I think you'll find that it is very, very similar:

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I agree, very similar! Thanks for clearing that up. Now my next question would be, is the one I have that passing voltage in both directions, defective?

Just an observation, I find it amazing how small these packages are and how complex they are when you look at them close up! In a former life I did laptop repair work and I was always amazed at how small they could make the fastening hardware! Screws so small that you had to pick them up with tweezers. But if I think about it, the fasteners used in wrist watches etc. are incredibly small as well. And they have been around much longer than the machinery that is used to create fasteners today.

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“To know, and not to do, is not to know”

Love this place, I learn so much.

Here's a photo for ya, SteveO:

https://www.circuitspecialists.com/1n34a.html

Now that I see that it is a point-contact diode, I'm less surprised that a typical DMM diode test would give such a high Vf: the current conduit is very narrow, so to reach the "test current" usually implemented (again, it looks like it may be 0.5 mA for SteveO's DMM; it's 0.4 mA for the DMM I currently use) the voltage will need to be higher than we would expect for a more conventional germanium PN junction diode.

I'm not sure what is going on with the 2.7 V reverse voltage for one of them, but it could reflect another aspect of the implementation of the diode test on that DMM.

I now feel like getting some 1N34A's and working out the I-V characteristic. I've done this for other diodes and some PN junctions of bipolar junction transistors, may as well grow my collection, not that I'm a nerd or anything.

You say nerd like it is a bad thing.
I have a few "1N34a" in my parts bin (see photo) but they look totally different than the one in the link above. I have learned in this forum that same value capacitors can be packaged in different ways. Does the same hold true for diodes as well? Is it possible I was I sent the incorrect ones? I have only used one of these in a circuit and pedal functioned as expected. I'd have to back and dig a little to find out what pedal I used it in and what's it's function in that circuit was... Looking at these under magnification it looks like C56V then underneath that is either a 5T or an ST printed on it.

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“To know, and not to do, is not to know”

Yeah but "the one in the link above" looks just like the "?" in your first photo, so I was offering that as strong support for duhvoodooman's suggestion that your "?" is a 1N34A.

In my experience, the key meaning of a designation like "1N34A" and "2N3904" and "4558" and so forth is how the component will perform in an electronic circuit (as advertised in the datasheets). Different manufacturers, or even the same one, may offer variations in packaging. The big row of orange ones in your last photo is an appearance very familiar to me from several different popular silicon diodes (esp. signal rather than rectifier) and the double-band job you marked "?" was the first time I'd ever see a double-banded one. But that web page from Circuit Specialists seems to conform to your "?" diode.

I have bought quite a few 1N34As over the years and most of them look like the ones you asked about in your first post WITH THE EXCEPTION OF THE PAINT MARKINGS. Those have been all over the place--one stripe, two stipes at one end (like yours), a stripe of one color at one end and another color at the other end, a stripe at one end and a dot at the other, and I haven't even gotten into how many different paint colors are used. But I've also received 34As like your last photo, and they were totally legit as well. As long as we're only talking about using them as clipping diodes, then as long as they measure out under 0.5V forward voltage (not counting Zener or Schottky diodes, which are different beasts), they pretty much have to be germaniums, since I've never heard of silicon diodes that low. And you'll also see other designations used, like 1N60, 1N270, D9D and several others. As far as using them for signal clipping, the vast majority seem to function the same. The low forward voltage is the main determinant.

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Got it! Thank you!

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“To know, and not to do, is not to know”

Good to know.
That being said, how would I go about testing the forward voltage. Just curious?

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“To know, and not to do, is not to know”

That's what the diode setting on your DMM does (though note that you need to get the polarization right); you were getting 0.386 V for one of them. Note that the forward voltage depends on how much current is going through the diode, but the voltage does not vary greatly with the current. So we typically see around 0.6 V for a silicon diode or 0.25 V (-ish) for a germanium one, when the current is on the order of 1 mA give or take a factor of 10. In essence, your DMM picks a target current, and varies the voltage across the diode until that current is what happens.

More generally you can arrange to measure the voltage across and the current through the diode at the same time, and vary the applied voltage to map out the relationship between the two. That's the nerd territory I was referring to earlier, and I think it's fair to say it's not needed for typical pedal building activities.

Great info! Thanks so much for sharing! I'm going to get out a few different kinds and see what I come up with. I've recently acquired a few Mad Bean PCB's and some of the component values in the BOM aren't listed, just what the forward voltages you should be shooting for in the ones you choose. New territory for me! Guess it's time to learn to look at data sheets before buying some of these parts.
Thank you again, for taking the time and patience to answer my questions!

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“To know, and not to do, is not to know”

Here ya go SteveO, chew on this if you like. For some Si diodes or other Si pn junctions, the currents as functions of the forward voltages.



And then another similar graph, but for some Ge diodes (but no 1N34A).

Wow! I'd love to chew on those a bit. Do you happen to have larger copies you could possibly email me? These old eyes ain't what they used to be.
If so I can PM you my email address.
Thanks!
-=Steve

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“To know, and not to do, is not to know”

Ha ha, in fact I reduced those x2 so they would not overwhelm everyone's browser window.
I'll try to include the originals in this post but not put them inline.
I think then you can download them somehow.
If it doesn't work maybe there is a way to use the internal messaging system here to pass them around.
Otherwise we can look at email.


edit: I dunno, it looks to me like they are in-line, and really hogging up space. Oh well.

Much easier to read! Thank you!! I was able to save them to my pc via a right mouse click.

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“To know, and not to do, is not to know”

Just like an NFT, but without the money laundering

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