Jump to content

Part Sourcing Assistance/Advice Thread


n_maher
 Share

Recommended Posts

Are the C32725's PNP or NPN? On-Semi and Fairchild datasheets indicate they are PNP  (BC327 range) but I've tested them out of an old Unison Research amp I'm fixing and they turn out to be NPN rather than PNP. Same goes for the C33725's (BC337) as spec'd as NPN but they test PNP in and out of the circuit.

They are old C32/33725 parts with the silver etched background on the TO92 transistors so apparantly the new BC327/337 range are modern replacements.

-font-b-C32725-b-font-C33725.jpg

Is this a datasheet error (which I find it hard to believe to be across 3 manufacturers) or are the BC337/327 completely different to the C32/33725's?

 

 

Edited by DefQon
Link to comment
Share on other sites

That was what I was thinking as well, although I can't seem to find any data sheet for a 2SC32725...

DefQon: Not sure if you you already know, but 2SCxxxx is an NPN BJT in the Japanese system (2SAxxxx is the corresponding PNP). BCxxx in the European system is a silicon small-signal BJT, but no mention of polarity.

//UFN

Link to comment
Share on other sites

21 hours ago, UFN said:

That was what I was thinking as well, although I can't seem to find any data sheet for a 2SC32725...

DefQon: Not sure if you you already know, but 2SCxxxx is an NPN BJT in the Japanese system (2SAxxxx is the corresponding PNP). BCxxx in the European system is a silicon small-signal BJT, but no mention of polarity.

//UFN

Yes but there is no such thing as 2SC32 or 33725. All Japanese 2SC/2SA have a model designation between 2-4 digits, not 5. I'm wondering if anybody knows the manufacturer for the above general purpose NPN/PNP transistor.

Link to comment
Share on other sites

On 11/27/2015, 8:38:27, DefQon said:

Are the C32725's PNP or NPN? On-Semi and Fairchild datasheets indicate they are PNP  (BC327 range) but I've tested them out of an old Unison Research amp I'm fixing and they turn out to be NPN rather than PNP. Same goes for the C33725's (BC337) as spec'd as NPN but they test PNP in and out of the circuit.

They are old C32/33725 parts with the silver etched background on the TO92 transistors so apparantly the new BC327/337 range are modern replacements.

-font-b-C32725-b-font-C33725.jpg

Is this a datasheet error (which I find it hard to believe to be across 3 manufacturers) or are the BC337/327 completely different to the C32/33725's?

 

 

I've got some BC327-25 and BC337-25. The 337s look just like yours, above, but test out as NPNs (and the 327s are PNPs). I think they came from an ebay seller (Parts4You or something like that).

Link to comment
Share on other sites

  • 3 weeks later...

Also check the Vbr with a DY294 transistor tester.

It pays to pay a bit more to get genuine parts from reliable suppliers.

Its not worth trying to save a few cents in the end it will cost you more dollars and time to fix the project

I learn it the hard way in my KGSShv build a few years ago.

Link to comment
Share on other sites

  • 2 weeks later...
Link to comment
Share on other sites

17 minutes ago, spritzer said:

That's just the pins and they are easy to open up.  Well a bit tedious when I had to do that to some 500 sockets... 

You mean the tail screw is easy to loose, right?
Put some solder on it can fix the problem, only do that after you screw up tightly!

Link to comment
Share on other sites

marginally related, but...

Does anyone know if a PCB fab will honor asymmetric ring sizes, as long as the annular ring specifications are met? So, basically I want the minimum ring size for the hole on the top of the PCB, but a significantly larger ring on the bottom? I don't see why not, I could accomplish the same thing with a ground pour and the subtracting from the solder mask...

Link to comment
Share on other sites

Since the top and bottom copper are separate layers in the Gerbers, I don't see why not?

So, my tool wouldn't do this, so I had to create a ground pour and attach it to each pin in the bottom, then subtract the solder mask via a pin swell parameter. I used the minimum annular ring on the part itself. I am getting the Gerbers ready to quote, so we will see.

Link to comment
Share on other sites

Dumb question, but anyone ever had problems with standoffs? I have some Keystone standoffs I bought from Mouser awhile back that I just tried out and none of the threads feel very smooth/precise when I screw them in. Two of them can't even be screwed into another standoff from the same package... I tried forcing it in one and now it's stuck (no swt jokes, please).

Link to comment
Share on other sites

Since the top and bottom copper are separate layers in the Gerbers, I don't see why not?
So, my tool wouldn't do this, so I had to create a ground pour and attach it to each pin in the bottom, then subtract the solder mask via a pin swell parameter. I used the minimum annular ring on the part itself. I am getting the Gerbers ready to quote, so we will see.

Ok, ordered. Interestingly, I ran it through OSH Park to see if they would kick anything back, and their board rendering showed the increased pin mask swell on the top as exposed copper, even though under the solder mask swell on the top there isn't any copper. That's odd.

I ended up ordering from PCB Way, as I got better lead-time and 2 more boards. Chose immersion gold, next step up in board thickness and 2 oz copper, and blue - the last three options best OSH. The FR4 spec that OSH uses was considerably more, not sure the what the Tg difference really entails. Shouldn't matter for my use.

I was tempted to have them delivered to me in China, but didn't want to risk mail routing issues.

I couldn't use Elecrow or Seeed because I exceed their width for their prototype (my boards are 12.5" wide) options. I still will use Elecrow for assembly though and maybe for another daughter board I need to whip up next.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.