Germanium and Silicon diodes comparison

thomasbe861 · Post by **thomasbe861** » 13 Oct 2023, 10:01

Long story short, I ended up testing and measuring a good part of all odd diodes I have had accumulated over the decades of tinkering.
Some are modern, widely available, some are more rare and not produced anymore, germanium, silicon, including Schottky, silicon carbide, Zener, LEDs, IR, etc.
Here are the graphs, showing the forward voltage drop for a given current (I-V curve) for different types of diodes. Hope this is helpful to anyone. All were measured using a Peak Atlas DCA75 Pro.

The legend for the graphs below and some detail about the testing, I tried to measure 100 of each type, for some of them I could not because I just did not have enough, for some others, the differences are marginal between each (1N400X, Zener, and most modern ones):

Average values of all diodes I measured (so far, I will add more later on):

Detailed values of all diodes I measured:

An example of what happens when I measured two different diode types in series. I read somewhere that depending on which one comes first, it affects the Vf of the pair, so I tried both setups:

Here you can find a picture of each diode type, individual graphics of measurements from the Peak DCA Pro app, different plots made using Matplotlib and Python (minimum, lower 10% outlier, median, mean, higher 10% outlier, maximum) for all these diodes, starting from the lowest Vf at 5mA up until the highest:

0.059V @ 5mA 19TQ015CJ These are the widely available regular ones

0.074V @ 5mA 95SQ015 These are the widely available regular ones

0.215V @ 5mA 1N5822 These are the widely available regular ones

0.233V @ 5mA 1N5817 These are the widely available regular ones

0.248V @ 5mA SR305-TP These are the widely available regular ones

0.254V @ 5mA D310 Д310

0.274V @ 5mA D311A Д311А

0.275V @ 5mA D311 Д311

0.299V @ 5mA D312 Д312

0.307V @ 5mA OA5 These are the Tesla ones

0.326V @ 5mA OA7

0.328V @ 5mA OA9

0.350V @ 5mA 1N60

0.355V @ 5mA BAT46 These are the widely available regular ones

0.381V @ 5mA GAZ51 These are the Tesla ones

0.388V @ 5mA 1D507A 1Д507А

0.405V @ 5mA D9G Д9Г

0.407V @ 5mA D9B Д9Б

0.415V @ 5mA 1D508A 1Д508А

0.417V @ 5mA D9K Д9К

0.422V @ 5mA D9D Д9Д

0.433V @ 5mA D9V Д9В

0.437V @ 5mA D9E Д9Е

0.459V @ 5mA D9L Д9Л

0.485V @ 5mA D9J Д9Ж

0.533V @ 5mA D20 Д20

0.537V @ 5mA D2E Д2Е These D2E are the glass ones with a blue stripe

0.537V @ 5mA 1N34A-2 I measured separately diodes of the same type but with different appearances, these 1N34A have two black stripes on the glass case

0.546V @ 5mA 1N5711

0.551V @ 5mA D18 Д18

0.618V @ 5mA D2J Д2Ж

0.621V @ 5mA D2V Д2В

0.623V @ 5mA 1N34A-1 These 1N34A have one black stripe on the glass case

0.625V @ 5mA BAT41 These are the widely available regular ones

0.626V @ 5mA D2EGr Д2Е These D2E are the gray painted ones

0.644V @ 5mA KD521V КД521В

0.652V @ 5mA 1N400X These are the widely available regular ones, 1N400X series seem to have the exact same curve (measured 1N4001, 1N4004, 1N4007)

0.678V @ 5mA 1N4148Y These are yellow 1N4148

0.687V @ 5mA D223B Д223Б

0.688V @ 5mA 1N4148 These are the widely available regular ones

0.694V @ 5mA 1N914 These are the widely available regular ones

0.708V @ 5mA KD522B КД522Б

0.710V @ 5mA D220 Д220

0.747V @ 5mA 1N277

0.755V @ 5mA 2D503B 2Д503Б

0.757V @ 5mA AA227

0.758V @ 5mA 1N4739A

0.765V @ 5mA 9V1 These are the widely available regular ones

0.782V @ 5mA ITTZPD9V1 These are 9V1 Zener by ITT

0.809V @ 5mA C3D02060A These are the widely available regular ones

0.829V @ 5mA WNSC2D04650Q These are the widely available regular ones

1.127V @ 5mA BIR-BM53E4G-2 These are the widely available regular ones

thomasbe861 · Post by **thomasbe861** » 19 Oct 2023, 11:53

Cant seem to be able to edit the post

Got some more to add

anyway I can edit this post?

Here are the mean for all diodes in a better display, with legend sorted by Vf @5mA.

Quality is not the best, native file is here and is called Diodes_Avg.svg: https://drive.google.com/drive/folders/ ... sp=sharing

the hyperlink to the HTML for having a detailed view of the graph, you can do a bunch of things using your web browser only, like filter out, zoom in, pan, etc.

Here are two examples of how you can filter out some diodes, zoom in and out, focus on a specific range, etc. e.g.: if you are looking for an alternative to a diode with the same I/V curve shape.

Gebrey · Post by **Gebrey** » 19 Oct 2023, 20:09

Great precise work. Thanks

Since the extreme vaiuable work I would put all in a PDF and attach it. Also spread that PDF on mayor guitar DIY communities.

:worship:

thomasbe861 · Post by **thomasbe861** » 20 Oct 2023, 04:27

Thanks Gebrey, sure will! I still got a few diode types to measure available at hand, I'll put it all in a PDF once complete

ppluis0 · Post by **ppluis0** » 20 Oct 2023, 11:13

Hi Thomas, and congratulations for your work !!

I think that you can trace the curves for Base-Emmiter diode junction of several bipolar transistors as they also can be employed as clipper devices in some cases.

Cheers,
Jose

thomasbe861 · Post by **thomasbe861** » 20 Oct 2023, 12:09

Hey Jose, thanks for the suggestion, if you are curious about any type in particular, let me know, I might also give a shot to MOSFETs and JFETs.
I will also publish the results on adding resistor(s), caps, inductors, etc. to the series and other different combinations to show how it affects the I/V curve.

Gebrey · Post by **Gebrey** » 21 Oct 2023, 10:14

Like IRF510, 2N7000, etc... the ones used as clipping diodes in famous pedals like Shaka braddah and OCDs

Manfred · Post by **Manfred** » 22 Oct 2023, 09:26

ppluis0 wrote: ↑20 Oct 2023, 11:13 Hi Thomas, and congratulations for your work !!

I think that you can trace the curves for Base-Emmiter diode junction of several bipolar transistors as they also can be employed as clipper devices in some cases.

Cheers,
Jose

Hello Jose, I agree with you on this.

As a reminder.
I found out, see this topic that the base-emitter diode of the MPSA18 is a good substitute for the MA858 diode.
viewtopic.php?t=382&start=380

Also Bajaman uses the BC557B base-emitter diode as a clipping diode in this topic.
viewtopic.php?t=28865

thomasbe861 · Post by **thomasbe861** » 22 Oct 2023, 11:13

Thnaks Manfred, I'll add these to the list to measure!

thomasbe861 · Post by **thomasbe861** » 24 Oct 2023, 09:11

Hi Manfred,
Can you send me the files containing the data for the PN Junction I / V from DCA Peak? I will add them to the general plot

Thanks!

Oh and here is the updated graph, I added a bunch from EI (Elektronska industrija Niš): https://drive.google.com/file/d/1bkDhEY ... sp=sharing
Just download the file and lunch it with your web browser.
You can filter for specific diodes, e.g.: for a specific curve shape:

Link to the folder with all data and graphs: https://drive.google.com/drive/folders/ ... sp=sharing
I will do the PDF when I have measured more.

Manfred · Post by **Manfred** » 24 Oct 2023, 12:18

Hi thomasbe861,

I am still away from home for a while, as soon as I am back I will trace again, I don not have the files anymore.

thomasbe861 · Post by **thomasbe861** » 25 Oct 2023, 22:34

I added some more, including 20 of these "1N34A" that are advertised on ebay as "20Pcs Germanium Diode 1N34A Diodes Instrument Parts Accessories 1N34 DO-35" for $2.48... added to the overall dataset:

Legend:

Average:

Folder:
https://drive.google.com/drive/folders/ ... sp=sharing

HTML:
https://drive.google.com/file/d/1bkDhEY ... sp=sharing

Detail:

0.391V @ 5mA 1N34Ch These are advertised on ebay as "20Pcs Germanium Diode 1N34A Diodes Instrument Parts Accessories 1N34 DO-35" for $2.48

luix · Post by **luix** » 28 Oct 2023, 16:50

Great work mate!!!

Can you also try to measure mosfet like BS170 in diode mode with Drain connected to Gate?

I've always used this configuration to have asymetrical clipping or soft clipping with a Vth of about 2V, I'm curious about the IV curve.

thomasbe861 · Post by **thomasbe861** » 29 Oct 2023, 12:43

Thanks luix; here you go, I added the 20 BS170 Vf between drain and source that I measured to the master file, just download the file and run it with your web browser to see how they compare to others: https://drive.google.com/file/d/1bkDhEY ... sp=sharing

I get an average of .667V @5mA; Here are the plots:

luix · Post by **luix** » 29 Oct 2023, 18:28

Thank you very much!

This is the body diode, the one that has anode on the source and catode on the drain, it is a sharp silicon diode.

If you invert the connection of the alligator clip and connect the red one (anode) on the drain-gate and the black one on the source the diode will show the Vth of the mosfet and it will be around 2V, the slope should be not so sharp and simulate a germanium one.

thomasbe861 · Post by **thomasbe861** » 29 Oct 2023, 21:26

Thanks luix; for some reason, I get no component detection between any other pins than drain and source, curve is flat between drain and gate or between gate and source, either forward or reverse voltage. When I measure the Vf between drain+gate and source, I get the same curve as between drain and source. between which should I measure?

@manfred; apparently the regulare 9.1v zener diodes have very similar characteristcs to the MPSA18 base emitter junction (therefore MA858 diodes), here are the graphs:

it seems even more obvious in the master file compared to all others:
https://drive.google.com/file/d/1bkDhEY ... sp=sharing

I know I got some MA858 hanging around somewhere, no MS856 though, I'll add these when I get my hands on them.

thomasbe861 · Post by **thomasbe861** » 30 Oct 2023, 09:49

Ciao luix, I tried several configurations and only got results when connecting drain and gate together on one side and the source on the other. All other curves are flat.

Typically, if you would hook up two MOSFET in parallel for your clipping circuit, you'd only get Vf and not the Vr, so 0.667V (at 5mA), third configuration below.

First configuration is what you get with gate open, drain to your signal and source to ground, Vf at 0.667 and Vr at 5.5V.
Second configuration, where drain and gate to your signal and source to ground, you'd get a Vf of 0.667 and Vr of 2.43V.

I get the same results with IRF510, IRF520, 2N700, etc., will add these to the master plot.

thomasbe861 · Post by **thomasbe861** » 30 Oct 2023, 15:05

I added these 1N34A advertised on eBay as "1N34A ITT / BKC, Now Microsemi Gold Bonded Germanium Diode, House Marked color coded bands /Black/Brown/Red/ Printed ITT logo on glass DO-7. Vf is in the .28-.30 range." Athough I haven't seen the ITT logo on them, 0.334V @ 5mA :

Very close to the "1N34A" ordered from China for a chunk of the price (2$ each vs 0.12$ each), even more to the BAT46 (0.11$ each).
Not so close to the 1N34A I got from Banzai Music in around 2009:

the snapshot of the master including these:

the interactive HTML:
https://drive.google.com/file/d/1bkDhEY ... sp=sharing

luix · Post by **luix** » 30 Oct 2023, 15:49

Ciao!

A mosfet connected in that way (D+G and S) is equivalent to two diode in antiparallel as below:

: MosDiode.jpg (21.15 KiB) Viewed 17656 times

Using a multimeter (fluke 175) is possible to detect the two different Vth diode.

Probably the Atlas is not able to detect the higher threshold diode due to the low working voltage, as far as I remember the internal battery is only 3V, what a pity

It depends on the clipping I would get but I usually put two MosDiode getting a soft clipping of about 3V per side.

thomasbe861 · Post by **thomasbe861** » 30 Oct 2023, 23:17

Oh alright, yup it does measure that, goes up to 12V,
so the matching curves for these configurations give these:

Germanium and Silicon diodes comparison [documentation]