Transistor data with sorting

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#21
Terry Demol said:
Greg

Nice work, the sorting function is great.
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Thanks.

Terry Demol said:
Is it worth adding a collector current column.
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Is it? I am not sure. Are you talking about just the VAS transistors or all groups?

I was hoping that each table would display the important specifications for the particular job in the amplifier circuit. Unfortunately, I am not that knowledgeable on component selection, so I am really seeking input from those that know.

With the VAS table, I am starting to realise that some of the transistors are obsolete. Should I add a column obsolete yes/no or just delete them?

regards
 
#22
Hi Greg,

Bloody brilliant!! Many thanks....

I think maybe collector current is important, but you seldom see TO126 below 50mA, and almost any VAS application can use these, so maybe not too significant in the chart.

Here's a couple for input stage, very high beta, 2SC1845, AND MPSA18.

Hugh
 
#23
Greg,

many thanks! One suggestion - make this into a diyAudio Wiki. That way it is always available at diyAudio, and others can add to it over time, meaning that you don't have to do all the updates. Also it is easy to attach datasheets.

I'm happy to help with that effort if you like.

mightydub
 
#24
Greg Erskine said:
With the VAS table, I am starting to realise that some of the transistors are obsolete. Should I add a column obsolete yes/no or just delete them?
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I think just remove them, except for the types which are still available through re-manufacture (e.g 2SC3953), though you might want to either put a footnote or a column indicating that it's no longer available as an original part.

As much as this is audio and people go crazy over NOS like rare diamonds, there's no point in trying to design around something that's no longer available. There's still plenty of alternate types which are as good or better than the obsoleted transistors in the case of the VAS anyway.
 
#25
AKSA said:
Hi Greg,

Bloody brilliant!! Many thanks....

I think maybe collector current is important, but you seldom see TO126 below 50mA, and almost any VAS application can use these, so maybe not too significant in the chart.

Here's a couple for input stage, very high beta, 2SC1845, AND MPSA18.

Hugh
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Thanks Hugh,

So any or most TO-126 or TO-220 devices will have sufficient collector current for a VAS. right?

Yes, I'll have to add a few more to the small signal list and drivers, thanks for the suggestions. Just recently the VAS topic seems to have been discussed in numerous threads hence the focus on them.

regards
 
#26
mightydub said:
Greg,

many thanks! One suggestion - make this into a diyAudio Wiki. That way it is always available at diyAudio, and others can add to it over time, meaning that you don't have to do all the updates. Also it is easy to attach datasheets.

I'm happy to help with that effort if you like.

mightydub
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Hi mightydub,

I had thought about the Wiki but it doesn't allow me to use javascript which makes the columns sortable. Maybe a Wiki landing page with selection criteria and reference links.

The links to datasheets is OK for current production components where the manufacture hosts the datasheets. The non-manufacture datasheet repositories I use don't allow direct linking. Maybe I should add a link or two to these datasheets repositories.

I don't have sufficient ISP storage to host the datasheets myself and my upload speed prevents me hosting the datasheets locally. I would prefer the datasheets be located in a single location, so the links will work and will continue to work once the component has become obsolete or a manufacture decides to redesign their web site structure. You see, I have thought about it but haven't found the ideal solution.

I may end up going with a less than ideal solution but at the moment I'm still thinking about it.:crazy:

regards
 
#27
mt490 said:
I think just remove them, except for the types which are still available through re-manufacture (e.g 2SC3953), though you might want to either put a footnote or a column indicating that it's no longer available as an original part.

As much as this is audio and people go crazy over NOS like rare diamonds, there's no point in trying to design around something that's no longer available. There's still plenty of alternate types which are as good or better than the obsoleted transistors in the case of the VAS anyway.
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Thanks mt490, I think I'll do as you suggest and add a column indicating availability (though this will require ongoing maintenance). As you say, having a reference to the "good old" components is desirable.

regards
 
#31
mt490 said:
I'd say use the "cheater's method" and link to the search of the manufacturer's homepage.

Search result

Anybody using your page should be confirming the data anyway, and are probably interested in more than what your site lists.
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Hi mt490,

Thanks, I have taken half your idea and implemented links to datasheets. :Present:

VAS Transistorshttp://users.tpg.com.au/gerskine/greg/vas transistors.htm

I have decided to use Datasheet4U.com and link to the transistor landing page. It is just a couple of clicks away from the actual datasheet and it allows you to select which manufacturer's datasheet you would prefer to reference.

regards
 
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#33
infinia said:
Hi
How adding about a status column to all sheets, yes in production, obsolete, or vintage collectors item.
Small signal BJT should state something about low noise, either data available on data sheet or N/A.
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Hi infinia,

Some good ideas, but I might just add a "notes" column to allow a little extra generic information for each transistor. I am a little concerned about having information that will require maintenance. (i.e. who is going to monitor the current availability of these transistors and some have been discontinued for years but are still commonly available)

I tend to prefer not having the information in preference to having some of information wrong. 😕

regards
 
#35
mt490 said:
I think just remove them, except for the types which are still available through re-manufacture (e.g 2SC3953), though you might want to either put a footnote or a column indicating that it's no longer available as an original part.
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Hi mt490,

I have added a notes column to the VAS transistors. I will do similar on the remaining groups depending on feedback.

VAS Transistors

regards
 
#36
Greg Erskine said:
Hi Hugh,

I have added these and started putting the links to the datasheets in.

PNP Small Signal Transistors

I probably need to add a column "suitable for" (i.e. LTP, current mirror, CCS etc.)

regards
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FWIW Links have a bad habit of either moving or disappearing all together. Wouldn't it be better to capture it and include an image or PDF in your database? More work up front, but long term usefulness and ease of maintainability. Not too sure about linking this web site as a guide datasheet4u.com at least it doesn't work at my computer. I tried them all, not one authentic PDF. might as well provide a link to Google LOL
 
#38
Hi infinai,

I just realised what is happening. Some NPN transistors do not have an PNP complimentary so I left the column empty. Not all links have been implemented yet, only 9 so far.

Also, when using datasheet4u, you need to select the PDF icon on the right, then select the Locate Datasheet link. I assume this "feature" has been included to prevent people linking directly to datasheets avoiding the advertisements.

regards
 
#40
taj said:
Greg, you're on the right track. Nice to see this happening. I can toss all my spreadsheets now. Thanks! And well-done!

..Todd
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Thanks Todd..

How was summer?

regards

infinia,

I have added all the links to the datasheet4u datasheets. A notes column has also been added.

Small Signal Transistors

Note: To see the latest changes, you may need to do a Refresh to clear cached pages.

regards
 
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