1N34A Germanium Diode finally found!!

On 08/28/2013 11:10 PM, sms wrote:
> On 8/28/2013 5:23 PM, Phil Hobbs wrote:
>> On 8/28/2013 8:18 PM, sms wrote:
>>> On 8/27/2013 7:27 PM, cgage.com@gmail.com wrote:
>>>> I finally found some 1n34a diodes and one of my new favorite sites!
>>>>
>>>> http://www.bgmicro.com/1n34a-germanium-diode.aspx
>>>
>>> I would have suggested Polypaks.
>>>
>>
>> Now _there's_ a blast from the past.  I remember when Digikey was Poly
>> Paks' main competitor, and Jameco was the gold standard. ;)
>
> I recall Jameco, well "James Electronics" as Digikey's competitor. Been
> using both of them for at least 35 years. My first job out of college
> was right across the street from James Electronics in San Carlos. Now I
> do will call if I need something fast.
>
> There were some other surplus companies that were Polypak's competition.
> A company in Florida called Knapp Electronics that printed their catalog
> on newsprint.
>

Yes, I think you're right--it was Digikey vs. Jameco and Poly Paks vs. 
the TV repair shop's dumpster. ;)

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

On 08/29/2013 01:52 AM, Greegor wrote:
>> I remember when Digikey was Poly Paks' > main competitor, and
>> Jameco was the > gold standard. ;)
>
> Electronics surplus was a blast back then. There was a Cortland
> Electronics that advertized in the ad section at the back of many
> electronic hobby magazines and had a short catalog of oddball stuff?
> I remember they got surplus stock of big old Burroughs Nixie tubes
> and circuit cards full of huge naked reed switches (originally
> intended for telephone switching?) Each reed was like 2 1/2 inches
> long and the sound they made when closed or opened was almost like a
> musical tuning fork.
>
> My Dad taught me how to do high quality soldering when I was 9 or so.
> I remember mounting an old tube TV power transformer in a box to
> power an elementary school science fair project where I recreated
> Edison's light bulb experiments by winding various types of iron wire
> around a large sewing needle to make tiny coils and knowing that
> vacuum and gas apparatus were out of reach for me at the time. The
> large amperage 6.3V tube filament power would make the filaments glow
> and then flare and burn open quite nicely. The higher voltage taps
> were stubbed and insulated for safety. It was a nice science fair
> project actually, kids liked seeing the filaments glow briefly and
> then burn open. Good for elementary school.
>
> At 12 I was building simple audio oscillators that used two
> multivibrator circuits so they warbled. My favorite used 2 PNP and 2
> NPN and by changing the various timing values the noise could be
> varied wildly. My Dad wanted a loud noisemaker for the business
> garage so I hung a power transistor and a big scavanged speaker at
> the end and the warble would cut through a lot of engine noise. I
> think I built that when I was like 13 and that loud thing kept
> running for a decade at least. After a few years it surprised
> somebody a bit too much so he put a pot or resistor in series with
> the speaker to drop the volume and it kept running for many years.
>
> By the time I was 18 I was building projects and buying parts from
> James Electronics (later Jameco) and Mouser. When I got into TTL I
> actually missed drawing traces and pads by hand using Sharpie markers
> as etch resist and etching with a bottle of Radio Shack Ferric
> Chloride. I could do a one off pretty fast. I'd go over the traces a
> second time with sharpie intil the sharpie ink was fairly dark to
> guarantee good resist. When I was in college, a few times I would
> wake up in the middle of the night with a TTL circuit idea I just had
> to commit to paper right away. At least two of them were TTL and did
> get built.
>
> The local electronics surplus retailers in Minneapolis had quite a
> heyday in the late 1970's as well. Some hobbyist printed up and
> handed out a map to the best dozen or so at one point. There was lots
> of really good mil grade stuff surplused off cheap.
>

There's a whole lot of generally pretty good Soviet stuff on eBay these 
days.  I got a career's worth of 15 nF feedthrough caps, small ceramic 
trimmers, small panel pots, and high-ohm resistors.

And the test equipment bonanza keeps on rolling.  There are a lot of 
dealers now, but even so, top quality boat anchors are going for a very 
few cents on the dollar.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

On Wed, 28 Aug 2013 20:10:38 -0700, sms <scharf.steven@geemail.com>
wrote:

>On 8/28/2013 5:23 PM, Phil Hobbs wrote:
>> On 8/28/2013 8:18 PM, sms wrote:
>>> On 8/27/2013 7:27 PM, cgage.com@gmail.com wrote:
>>>> I finally found some 1n34a diodes and one of my new favorite sites!
>>>>
>>>> http://www.bgmicro.com/1n34a-germanium-diode.aspx
>>>
>>> I would have suggested Polypaks.
>>>
>>
>> Now _there's_ a blast from the past.  I remember when Digikey was Poly
>> Paks' main competitor, and Jameco was the gold standard. ;)
>
>I recall Jameco, well "James Electronics" as Digikey's competitor. Been 
>using both of them for at least 35 years. My first job out of college 
>was right across the street from James Electronics in San Carlos. Now I 
>do will call if I need something fast.
>
>There were some other surplus companies that were Polypak's competition. 
>A company in Florida called Knapp Electronics that printed their catalog 
>on newsprint.

There a company with all kinds of cool stuff called Meshna?? or
something like that. 

John Larkin wrote:
> On Wed, 28 Aug 2013 22:55:24 +0000, chris <meru@devnull.com> wrote:
> 
>> On 08/28/13 17:53, Jim Thompson wrote:
>>
>>> In the mid to late '80's I used 1N270's by the bucket load to clamp
>>> LM324 and LM329 inputs, to avoid substrate diode injection and phase
>>> inversion.
>>> 		
>>>                                          ...Jim Thompson
>> Anyone remember the GE "back" diodes ?. Same can as their tunnel diodes,
>> but, iirc, very low forward voltage...
>>
>> Chris
> 
> People still make Ge back diodes, as rf detectors. They are, I think,
> the only planar "ic" type fabrication done in germanium, except
> photodiodes maybe.
> 

In Europe we had mesa and planar Ge RF transistors. For example, this
one was a hot commodity among the "discarded TV set pilfering" crowd
because you could often find them hidden as the only transistors in tube
sets:

http://html.alldatasheet.com/html-pdf/44095/SIEMENS/AF239/244/1/AF239.html

[...]

-- 
Regards, Joerg

http://www.analogconsultants.com/

Jim Thompson wrote:
> On Wed, 28 Aug 2013 20:36:20 -0400, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
> 
>> On 8/28/2013 7:37 PM, John Larkin wrote:
>>> On Wed, 28 Aug 2013 22:55:24 +0000, chris <meru@devnull.com> wrote:
>>>
>>>> On 08/28/13 17:53, Jim Thompson wrote:
>>>>
>>>>> In the mid to late '80's I used 1N270's by the bucket load to clamp
>>>>> LM324 and LM329 inputs, to avoid substrate diode injection and phase
>>>>> inversion.
>>>>> 		
>>>>>                                           ...Jim Thompson
>>>> Anyone remember the GE "back" diodes ?. Same can as their tunnel diodes,
>>>> but, iirc, very low forward voltage...
>>>>
>>>> Chris
>>> People still make Ge back diodes, as rf detectors. They are, I think,
>>> the only planar "ic" type fabrication done in germanium, except
>>> photodiodes maybe.
>>>
>>> http://www.aeroflex.com/AMS/Metelics/pdfiles/MBD_Series_Planar_Back_Tunnel_Diodes.pdf
>>>
>>> They conduct better in the reverse direction than forward, hence the
>>> name.
>> Making an AM detector that has both good linearity and a reasonable 
>> dynamic range is one of those deceptively hard problems.
>>
>> I tend to do one of two things: one or more DLVAs (e.g. SA614s) with 
>> some auxiliary calibrator, such as a crystal ringing down, or a PLL with 
>> fairly careful offset nulling.
>>
>> Ring-down calibration is convenient, because your average 80 MHz crystal 
>> rings down at something like 1 dB/ms or a bit less.  You can anchor the 
>> high-amplitude end with linear measurements, and rely on the exponential 
>> falloff for the lower-amplitude range.
>>
>> Cheers
>>
>> Phil Hobbs
> 
> Does anyone actually use just a diode for AM detection anymore?
> 		

<raises hand>

-- 
Regards, Joerg

http://www.analogconsultants.com/

On Tue, 27 Aug 2013 23:30:04 -0500, "Tim Williams" <tmoranwms@charter.net>
wrote:

>"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in 
>message news:k2tq19hm62ir3fttudo16p2vu4meefdnk1@4ax.com...
>> On Tue, 27 Aug 2013 19:27:37 -0700 (PDT), cgage.com@gmail.com wrote:
>>
>>>I finally found some 1n34a diodes and one of my new favorite sites!
>>>
>>>http://www.bgmicro.com/1n34a-germanium-diode.aspx
>>
>> What do you want it for? A low-barrier schottky is probably better for 
>> most
>> uses.
>
>Hmm, Vf and leakage are about the same, aren't they... tempco might be a 
>bit better for the schottky, it'll still be working around 100C (albeit 
>not so well) whereas the 1N34 will be a bad resistor.
>
>Speaking of resistors, I seem to recall testing point-contact diodes 
>before and seeing a couple of variations.  Some (presumably, the oldest 
>and lowest-current types) are good resistors past, you know, 0.2V or so. 
>Others are good diodes up to much higher currents (not as good as, but 
>more like, modern diodes).
>
>Even if you had a diode with Vf ~= 0 and a lot of Rs, as long as Ir isn't 
>too bad, it wouldn't be so bad overall -- since it remains more linear, 
>distortion won't be so bad.  SNR will be worse, of course, since the 
>desired signal is accordingly weaker.
>
>And hey, there's always 6AL5.  I've pushed them to peak currents over 50mA 
>before just fine, and they have very nearly zero charge (SiC schottky 
>can't compare in capacitance).
>
>Tim

WWII radars used silicon, germanium, and even gaas point-contact diodes. One of
the RadLab books casually mentions that "a semiconductor triode should be
possible."

One whole volume of the RadLab books is "Crystal Rectifiers." They knew a lot
about semiconductor physics in 1940.

https://dl.dropboxusercontent.com/u/53724080/Parts/RadLabDiodes.JPG




-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

On 8/29/2013 6:43 AM, Phil Hobbs wrote:

<snip>

> Yes, I think you're right--it was Digikey vs. Jameco and Poly Paks vs.
> the TV repair shop's dumpster. ;)

Poly Paks ad:
<http://www.flickr.com/photos/oskay/4455981283/sizes/l/in/photostream/>

On Thu, 29 Aug 2013 07:43:18 -0700, Joerg <invalid@invalid.invalid> wrote:

>John Larkin wrote:
>> On Wed, 28 Aug 2013 22:55:24 +0000, chris <meru@devnull.com> wrote:
>> 
>>> On 08/28/13 17:53, Jim Thompson wrote:
>>>
>>>> In the mid to late '80's I used 1N270's by the bucket load to clamp
>>>> LM324 and LM329 inputs, to avoid substrate diode injection and phase
>>>> inversion.
>>>> 		
>>>>                                          ...Jim Thompson
>>> Anyone remember the GE "back" diodes ?. Same can as their tunnel diodes,
>>> but, iirc, very low forward voltage...
>>>
>>> Chris
>> 
>> People still make Ge back diodes, as rf detectors. They are, I think,
>> the only planar "ic" type fabrication done in germanium, except
>> photodiodes maybe.
>> 
>
>In Europe we had mesa and planar Ge RF transistors. For example, this
>one was a hot commodity among the "discarded TV set pilfering" crowd
>because you could often find them hidden as the only transistors in tube
>sets:
>
>http://html.alldatasheet.com/html-pdf/44095/SIEMENS/AF239/244/1/AF239.html
>
>[...]

There were big TO3 and stud Ge power transistors, and I'm guessing that they
were a planar structure. If anybody has one, maybe they could decap it and take
pictures.

Germanium Power Devices was, I think, the last maker of Ge diodes and
transistors. They are now "GPD" and make photodiodes.

I think someone still makes Ge tunnel diodes.


-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

John Larkin wrote:
> On Thu, 29 Aug 2013 07:43:18 -0700, Joerg <invalid@invalid.invalid> wrote:
> 
>> John Larkin wrote:
>>> On Wed, 28 Aug 2013 22:55:24 +0000, chris <meru@devnull.com> wrote:
>>>
>>>> On 08/28/13 17:53, Jim Thompson wrote:
>>>>
>>>>> In the mid to late '80's I used 1N270's by the bucket load to clamp
>>>>> LM324 and LM329 inputs, to avoid substrate diode injection and phase
>>>>> inversion.
>>>>> 		
>>>>>                                          ...Jim Thompson
>>>> Anyone remember the GE "back" diodes ?. Same can as their tunnel diodes,
>>>> but, iirc, very low forward voltage...
>>>>
>>>> Chris
>>> People still make Ge back diodes, as rf detectors. They are, I think,
>>> the only planar "ic" type fabrication done in germanium, except
>>> photodiodes maybe.
>>>
>> In Europe we had mesa and planar Ge RF transistors. For example, this
>> one was a hot commodity among the "discarded TV set pilfering" crowd
>> because you could often find them hidden as the only transistors in tube
>> sets:
>>
>> http://html.alldatasheet.com/html-pdf/44095/SIEMENS/AF239/244/1/AF239.html
>>
>> [...]
> 
> There were big TO3 and stud Ge power transistors, and I'm guessing that they
> were a planar structure. If anybody has one, maybe they could decap it and take
> pictures.
> 
> Germanium Power Devices was, I think, the last maker of Ge diodes and
> transistors. They are now "GPD" and make photodiodes.
> 
> I think someone still makes Ge tunnel diodes.
> 

These guys seem to still build Ge-diodes:

http://wxecl.en.china.cn/

But they state that they get the materials from overseas, so probably
fabless.

-- 
Regards, Joerg

http://www.analogconsultants.com/

On 8/29/2013 11:30 AM, SMS wrote:
> On 8/29/2013 6:43 AM, Phil Hobbs wrote:
>
> <snip>
>
>> Yes, I think you're right--it was Digikey vs. Jameco and Poly Paks vs.
>> the TV repair shop's dumpster. ;)
>
> Poly Paks ad:
> <http://www.flickr.com/photos/oskay/4455981283/sizes/l/in/photostream/>

"You're getting the same type of material that the RE-TESTERS DO!"

Classic.

Cheers

Phil Hobbs


-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510 USA
+1 845 480 2058

hobbs at electrooptical dot net
http://electrooptical.net