So I got a bunch of these from China for a couple dollars. How can I tell they are not fakes and does it matter if I'm just going to stash them in my junk box and I don't expect any critical applications. In general, what's the right way to go about validating parts coming from China?
Chinese Germanium 1N34
Started by ●February 4, 2015
Reply by ●February 5, 20152015-02-05
On Thursday, February 5, 2015 at 12:01:20 PM UTC+11, M. Hamed wrote:> So I got a bunch of these from China for a couple dollars. How can I tell they are not fakes and does it matter if I'm just going to stash them in my junk box and I don't expect any critical applications. > > In general, what's the right way to go about validating parts coming from China?The drop across a germanium diode is less that that of a silicon diode, say 0.3 vs 0.6 for silicon Owen
Reply by ●February 5, 20152015-02-05
Owen Cook prodded the keyboard> On Thursday, February 5, 2015 at 12:01:20 PM UTC+11, M. Hamed wrote: >> So I got a bunch of these from China for a couple dollars. How can >> I tell they are not fakes and does it matter if I'm just going to >> stash them in my junk box and I don't expect any critical >> applications. >> >> In general, what's the right way to go about validating parts >> coming from China? > > > > > The drop across a germanium diode is less that that of a silicon > diode, say 0.3 vs 0.6 for silicon > > > OwenAnd are they not point contact devices. -- Best Regards: Baron.
Reply by ●February 5, 20152015-02-05
M. Hamed wrote:> So I got a bunch of these from China for a couple dollars. How can I tell they are not fakes** Test all the important parameters and compare with the 1N31 data sheet. and does it matter if I'm just going to stash them in my junk box and I don't expect any critical applications. ** Might if they turned out to be zeners.> In general, what's the right way to go about validating parts coming from China?** Avoid them completely - idiot. Only buy from authorised dealers. .... Phil
Reply by ●February 5, 20152015-02-05
On Wed, 4 Feb 2015, M. Hamed wrote:> So I got a bunch of these from China for a couple dollars. How can I > tell they are not fakes and does it matter if I'm just going to stash > them in my junk box and I don't expect any critical applications. > > In general, what's the right way to go about validating parts coming > from China? >A "1N34" is a pretty generic part. It existed, but the main point was that it was a (small signal) germanium diode. So long after there were other similar diodes, "1N34" became a generic indicator of a "small signal germanium diode". People didn't care what they got, so long as it was that type of diode. The only other small signal germanium diode I ever remember being specified in hobby magazines was the 1N82, which was also a small signal germanium diode but was good to UHF frequencies. They were apparently used in old UHF tv tuners, the kind that used a single diode mixer, the 1N82 being that diode mixer. I have no idea if the 1N82 was commonly used in that application, but again the part number became descriptive, if you saw it you knew it was germanium, and for higher frequency use. A "1N34" by definition isn't fussy. You need a germanium diode for its low forward voltage drop, that's really the only reason to specify a germanium diode. I suppose there might be some temperature sensitive application, but I don't recall that. Are they germanium? That seems to be the most important thing. Use the diode tester on your DMM. A silicon diode will indicate around .5, a germanium will indicate lower (enough lower that you can sort them that way) and schottky diodes will indicate something else (I can't remember what). Compare a germanium diode with a silicon (and a schottky for that matter), starting with known diodes, and you'll get the picture. I was actually surprised. About 15 years ago I needed a germanium dioded for something, and started looking through scrap boards. i was suprised that germanium diodes were more common than I'd expect. Michael
Reply by ●February 5, 20152015-02-05
On Wednesday, February 4, 2015 at 8:01:20 PM UTC-5, M. Hamed wrote:> So I got a bunch of these from China for a couple dollars. How can I tell they are not fakes and does it matter if I'm just going to stash them in my junk box and I don't expect any critical applications. > > In general, what's the right way to go about validating parts coming from China?I've got some of those Vf= 0.365V with my fluke DMM (i ~1 mA) George H.
Reply by ●February 6, 20152015-02-06
M. Hamed wrote:> So I got a bunch of these from China for a couple dollars. How can I tell they are not fakes** Err - try visual inspection first: http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg ... Phil
Reply by ●February 7, 20152015-02-07
On Friday, February 6, 2015 at 7:10:08 PM UTC-7, Phil Allison wrote:> M. Hamed wrote: > > > So I got a bunch of these from China for a couple dollars. How can I tell they are not fakes > > ** Err - try visual inspection first: > > http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg > > > > ... PhilThey look nothing like that. But if 1N34 is a pretty generic diode, there could be more than one manufacturer I assume. The drop is about .2-.3V but the first datasheet I looked up, doesn't match the parameters I'm getting.
Reply by ●February 7, 20152015-02-07
On Sat, 7 Feb 2015 12:46:07 -0800 (PST), "M. Hamed" <mhdpublic@gmail.com> wrote:>On Friday, February 6, 2015 at 7:10:08 PM UTC-7, Phil Allison wrote: >> M. Hamed wrote: >> >> > So I got a bunch of these from China for a couple dollars. How can I tell they are not fakes >> >> ** Err - try visual inspection first: >> >> http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg >> >> >> >> ... Phil > >They look nothing like that. But if 1N34 is a pretty generic diode, there could be more than one manufacturer I assume. > >The drop is about .2-.3V but the first datasheet I looked up, doesn't match the parameters I'm getting.1N34s could be all over the place. Point contacts are sorta random. They have a high series resistance, so the low voltage drop of germanium only happens at very low currents. Germanium is silly, when silicon schottky diodes are available. -- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●February 8, 20152015-02-08
M. Hamed prodded the keyboard> On Friday, February 6, 2015 at 7:10:08 PM UTC-7, Phil Allison wrote: >> M. Hamed wrote: >> >> > So I got a bunch of these from China for a couple dollars. How >> > can I tell they are not fakes >> >> ** Err - try visual inspection first: >> >> http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg >> >> >> >> ... Phil > > They look nothing like that. But if 1N34 is a pretty generic diode, > there could be more than one manufacturer I assume. > > The drop is about .2-.3V but the first datasheet I looked up, > doesn't match the parameters I'm getting.No it doesn't look like any of my 1N34's either ! -- Best Regards: Baron.
