Tayda's germanium diodes

[GoranP]

My ebay "1n34a"s are here... never had this type...



I measured 10 of them and they consistently show 170-180. Dunno... is it my DMM or are they again "fake"? The ones I got from GuitarPCB measure ~300...

[Dave]

Interesting, that sounds rather low, I've never seen that type either. Hmm, so it looks like we're yet to find a cheap and reliable source for these.
Thanks
Dave

[GoranP]

OTOH, I found this...

http://www.diystompboxes.com/smfforum/index.php?topic=856.0;wap2

"My experience is that there is a little more variation than what Brett suggested.  I get Ge diodes with anywhere from a 180mv to 320mv forward voltage spec, and Si diodes with anywhere from 400mv to 700mv specs."

and this

http://www.satcure-focus.com/tutor/page3.htm"

"Germanium diode = 0.2v"

and even this

http://bftgu.solarbotics.net/starting_elect_semic_1j.html

" Germanium diodes (for example, the 1N34A) have a forward voltage drop of about 0.1 volt. Germanium diodes, though, are typically much more expensive than silicon diodes; luckily, they're salvageable from lots of circuit boards. To test whether or not a diode is Germanium, get out your multimeter, put it on diode test, and measure the diode's forward voltage drop directly. A Germanium diode will read less than 0.3, a Silicon will read above 0.5."


Now I'm completely baffled. Anyone with more experience in these matters? Mark?

[IvIark]

I've got them that read anywhere from 0.2V to 0.4V, but it also depends what I use to measure them.  The Peak doesn't seem to like measuring germanium diodes and often threw up a voltage drop of 0.5 to 0.7V, but when I checked them in my other two meters, they were between 0.3 and 0.35V.  From everything I've read I would expect that to be pretty much perfect for germanium diodes.   I've bought diodes marked 1N34A in about 3 different styles now, and really don't know which ones are authentic and so the benchmark, but to me 0.3 to 0.35 is what I have always considered to be the right range.

[JaviCAP]

The ones I use are from gc_supermarket , something like 50 pieces / 6 euros including s&h.

No problem  so far, an all diodes read between 260 and 290, so pretty good in my opinion.

BR

[johnk]

I agree with Mark. .3-.35V is what 1N34A's should be.

[GoranP]

JaviCAP wrote

The ones I use are from gc_supermarket , something like 50 pieces / 6 euros including s&h.

No problem  so far, an all diodes read between 260 and 290, so pretty good in my opinion.

I just checked the ebay listing, mine are from gc as well ane measure 170. Now, if my dmm's internal resistance is weird and these would be 300ish on your dmm, then the ones I have in 300ish are actually more.

[johnk]

BTW, my vintage 1966 NOS telefunken 1N34A's measure .328V and are very consistent, and they have 1N34A printed on their clear glass bodies

[IvIark]

Have you got a pic of them John.  Just wondering if they look anything like the non-Chinese black band 1N34A's that I've got.

Incidentally, I've noticed a lot more sellers on eBay selling big lots of 1N34A diodes in a DO35 package which look exactly like 1N4148's.   As far as I'm aware 1N34As should be a D07 package (every datasheet I've ever found have been DO7s), and I suspect the DO35 diodes sold as 1N34A's are really schottky's.   Be careful what you buy.

[johnk]

NOS Telefunken 1N34A's:

[johnk]

BTW, I agree about the ones that look like 4148's. there are 1N60's that look like that too and I believe that they are also schottky's.

[GoranP]

John, these look exactly like the ones I got from GuitarPCB (measuring ~300).

I'm guessing my GC batch could be usable, it certainly beats blown diodes or the ones in 2+V range.

BTW, I've contacted them about the funny FVD and they said that they "aren't sure" about diode specs. Not very inspiring for future purchases, especially since they are on my short "funny business" list along with Polida. I've received some good stuff from them both but every time the order looks suspicious and sometimes even with faulty components.
My last order of 10 PT2399s contained ICs with four quite different stencils on them, also in different shade of plastic. Only two or three actually looked like the real deal (even that is debatable since I don't know for sure what's supposed to be on the bottom side), others were a little or completely different. Nothing inherently wrong with that as there are probably many legit factories and makers but it just looks suspicious when you order 10 (not 10000, mind you) and you get 7 different ones. Makes you wonder what their storage facilities look like when they can't even match 10 pieces in appearance (at least, if not function).