Chinese Germanium 1N34

[M. Hamed]

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?

 

[Owen Cook]

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

 

[Phil Allison]

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

 

[Baron]

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


Owen

And are they not point contact devices.

--
Best Regards:
Baron.

 

[George Herold]

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.

 

[Michael Black]

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

 

[Phil Allison]

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

 

[M. Hamed]

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.

 

[John Larkin]

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

 

[Baron]

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.

 

[Phil Allison]

Baron wrote:

** Err - try visual inspection first:

http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg



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 !

** Wot - not clear glass and no die on the end of a header or tiny wire making a point contact?

Sure your 1N34s are genuine ?




..... Phil

 

[Phil Allison]

Baron wrote:

** Err - try visual inspection first:

http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg



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 !


** Wot - not clear glass and no die on the end of a header or tiny
wire making a point contact?

Sure your 1N34s are genuine ?


Oops, Sorry Phil, Guys. A brain fart !
I've just looked at the ones I have, they are 1N23. Still in the lead
foil packets.

** So they look like little bullets:

http://www.ciel-electronique.com/catalogue/Larges/JAN1N23WE.jpg



.... Phil

 

[Baron]

Phil Allison prodded the keyboard

Baron wrote:


** Err - try visual inspection first:

http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg



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 !


** Wot - not clear glass and no die on the end of a header or tiny
wire making a point contact?

Sure your 1N34s are genuine ?




.... Phil

Oops, Sorry Phil, Guys. A brain fart !
I've just looked at the ones I have, they are 1N23. Still in the lead
foil packets.

--
Best Regards:
Baron.

 

[Michael Black]

On Mon, 9 Feb 2015, Baron wrote:

Phil Allison prodded the keyboard

Baron wrote:


** Err - try visual inspection first:

http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg



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 !


** Wot - not clear glass and no die on the end of a header or tiny
wire making a point contact?

Sure your 1N34s are genuine ?




.... Phil

Oops, Sorry Phil, Guys. A brain fart !
I've just looked at the ones I have, they are 1N23. Still in the lead
foil packets.

SO they are microwave diodes. Apparently they don't want much current
through them, one was not supposed to use a VOM to check them (so I'm not
sure if a DMM is acceptable or not).

That's the progression. In WWII, they worked on radar, improving it and
finding that they needed to move up in frequency in order to get good
enough definition. In doing so, they helped pave the way for more use of
those higher frequencies after the war. They were able to get tubes to
transmit up there (by making new types of tubes) but had problems with
tubes that operated up there. So they went to crystal diode mixers, and
went back to the "cat's whisker" of the early days, except making it more
stable, so you didn't have to fiddle to find where on the surface there
was good operation. And that caused the 1N34 to come along after the war,
and it caused Bell to look at the transistor after the war. I forget the
title, but there is a book about this, something about the invention that
changed the war, which is interesting in telling the story of Radar
development during WWII, and its impact after the war.

I noticed something interesting related to the 1N34 a few years ago. I
had downloaded a 1930s copy of The Radio Handbook and one of the people
thanked at the beginning was Rufus P. Turner. A name that was quite
familiar in the hobby electronic and amateur radio magazines at one time.
SInce I remember his articles about solid state devices, I assumed he was
a relative newcomer, but no, he'd been involved since the earlier days of
radio. SOme of those writer's names were so constant, yet we knew so
little about them other than what they published. I got curious, and
looked, and it turned out Rufus P. Turner was black. He got a platform,
at a time when he might not if people knew he was black. When I got
interested in electronics the local library had one of his books from the
fifties, interesting projects, that I took out endlessly (since there
wasn't much selection). And then maybe a decade ago, I found a near
perfect copy of that book at a book sale for no more than a dollar. So it
was kind of neat to learn that he was black.

That wasn't a sidetrack. IN reading up on him, apparently he was involved
(though it's not specified in what way) in the development of the 1N34 at
Sylvania. Small signal germaninum diodes are still referred to in a
generic sense as "1N34", and he had something to do with that.

Michael

 

[Phil Allison]

Baron wrote:

Oops, Sorry Phil, Guys. A brain fart !

I've just looked at the ones I have, they are 1N23. Still in the
lead foil packets.


** So they look like little bullets:

http://www.ciel-electronique.com/catalogue/Larges/JAN1N23WE.jpg



Yes those are the ones I've got.

** Dems are *silicon* point contact diodes.



..... Phil

 

[Baron]

Phil Allison prodded the keyboard

Baron wrote:


** Err - try visual inspection first:

http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg



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 !


** Wot - not clear glass and no die on the end of a header or
tiny wire making a point contact?

Sure your 1N34s are genuine ?


Oops, Sorry Phil, Guys. A brain fart !
I've just looked at the ones I have, they are 1N23. Still in the
lead foil packets.


** So they look like little bullets:

http://www.ciel-electronique.com/catalogue/Larges/JAN1N23WE.jpg



... Phil

Yes those are the ones I've got.

--
Best Regards:
Baron.

 

[David Eather]

On Mon, 09 Feb 2015 11:03:05 +1000, Phil Allison <pallison49@gmail.com>
wrote:

Baron wrote:


** Err - try visual inspection first:

http://www.lessmiths.com/~kjsmith/crystal/s1N34A-3.jpg



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 !


** Wot - not clear glass and no die on the end of a header or tiny wire
making a point contact?

Sure your 1N34s are genuine ?



.... Phil

Do these ones look OK? I can't tell, my eyes keep going watery. (Anyone on
heart meds should not open the link!)

http://www.ebay.com/itm/X-1-pcs-1N34A-Germanium-Diode-1st-class-post-uk-guitar-effects-pedal-use-/261498065100?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3ce27fd0cc

 

[George Herold]

On Saturday, February 7, 2015 at 7:44:05 PM UTC-5, John Larkin wrote:

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

OK for fun I did the I-V of a 1N34.

https://www.dropbox.com/s/gyolf6cj5cd8erw/1N34.BMP?dl=0

I thought Germanium were supposed to be "more ideal" than Si diodes.
But the point contact thing looks nothing like the ideal diode model.
(log/ linear plot)

George H.

 

[George Herold]

On Wednesday, February 11, 2015 at 11:56:16 AM UTC-5, John Larkin wrote:

On Wed, 11 Feb 2015 07:47:54 -0800 (PST), George Herold
gherold@teachspin.com> wrote:

On Saturday, February 7, 2015 at 7:44:05 PM UTC-5, John Larkin wrote:
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

OK for fun I did the I-V of a 1N34.

https://www.dropbox.com/s/gyolf6cj5cd8erw/1N34.BMP?dl=0

I thought Germanium were supposed to be "more ideal" than Si diodes.
But the point contact thing looks nothing like the ideal diode model.
(log/ linear plot)

George H.

Yeah, the Ge is going ohmic past roughly 1 mA. But another 1N34 might
be very different.

Try a small-signal schottky, 1N5711 maybe. That's a high-barrier part.
The low-barrier parts, rated a few volts reverse, are even better.

OK 1N5711 added to plot... I think you can use the same dropbox link.

George H.

--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[John Larkin]

On Wed, 11 Feb 2015 07:47:54 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

On Saturday, February 7, 2015 at 7:44:05 PM UTC-5, John Larkin wrote:
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

OK for fun I did the I-V of a 1N34.

https://www.dropbox.com/s/gyolf6cj5cd8erw/1N34.BMP?dl=0

I thought Germanium were supposed to be "more ideal" than Si diodes.
But the point contact thing looks nothing like the ideal diode model.
(log/ linear plot)

George H.

Yeah, the Ge is going ohmic past roughly 1 mA. But another 1N34 might
be very different.

Try a small-signal schottky, 1N5711 maybe. That's a high-barrier part.
The low-barrier parts, rated a few volts reverse, are even better.


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com