Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

NPN & PNP pin ID

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

mdnanwelch7(at)hotmail.co
Guest

Posted: Tue Sep 21, 2010 9:26 am Post subject: NPN & PNP pin ID

Group,

  

   I'm in the middle of building the circuit Bob N. designed for the IvoProp current

 limiter.

  

   I've got most of the things soldered to my little board, and now I'm ready to start tying

 everything together with the resistors.  I've done some homework, and made sure I

 got the polarity squared away for my diodes, capacitor, and what-nots.

  

   Here's the problem...the transistors!!  I've looked up the NPN 2N3904 and the PNP 2N3906 

 data sheets, and thought I had the 1, 2, 3-collector, base, emitter all figured out.

  

   Then, just to make sure I was on the right track, I called up a different 2N3904

 data sheet.......and it was BACKWARDS from the first one I just looked at!!!!  Now I

 don't know who's lies to believe!!

  

   Can someone please be kind enough to steer me in the right direction for the 

 CORRECT pin ID on the two resistors I listed.

  

 Thanks,  Mike Welch

 		 	   		    [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

david.nelson(at)pobox.com
Guest

Posted: Tue Sep 21, 2010 9:50 am Post subject: NPN & PNP pin ID

Hi Mike,



A isometric picture is worth a 1001 words:



http://www.fairchildsemi.com/ds/2N/2N3904.pdf



Regards,

 	 /\/elson



~~  Lately my memory seems to be like a steel trap .... without any spring.  ~~



On Tue, 21 Sep 2010, Mike Welch wrote:



 	  Quote: 	
		   Group,



   I'm in the middle of building the circuit Bob N. designed for the IvoProp current

 limiter.



   I've got most of the things soldered to my little board, and now I'm ready to start tying

 everything together with the resistors.  I've done some homework, and made sure I

 got the polarity squared away for my diodes, capacitor, and what-nots.



   Here's the problem...the transistors!!  I've looked up the NPN 2N3904 and the PNP 2N3906

 data sheets, and thought I had the 1, 2, 3-collector, base, emitter all figured out.



   Then, just to make sure I was on the right track, I called up a different 2N3904

 data sheet.......and it was BACKWARDS from the first one I just looked at!!!!  Now I

 don't know who's lies to believe!!



   Can someone please be kind enough to steer me in the right direction for the

 CORRECT pin ID on the two resistors I listed.

 

 Thanks,  Mike Welch

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

mdnanwelch7(at)hotmail.co
Guest

Posted: Tue Sep 21, 2010 10:44 am Post subject: NPN & PNP pin ID

 	  Quote: 	
		   A isometric picture is worth a 1001 words:


	


 	  Quote: 	
		   Regards,

 /\/elson


	


  /Velson,

 

  Thanks for the link, but it was one of the two I was already looking at

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

retasker(at)optonline.net
Guest

Posted: Tue Sep 21, 2010 3:26 pm Post subject: NPN & PNP pin ID

There are, in fact, versions with different pin-outs.  Not just a 

different pin numbering scheme, but BCE connected to different physical 

pin locations.  I got bit by this once upon a time.

The only way to know exactly what you have is to know who made the part 

(specific part number) and look at their data sheet.

You can do basic checking with your ohmmeter to easily find the base, 

but you would need a transistor tester to ID the E vs C.  Some 

multi-meters have this capability built-in.

Dick Tasker

Mike Welch wrote:

 	  Quote: 	
		   > A isometric picture is worth a 1001 words:

 > Regards,

 > /\/elson

   /Velson,

   Thanks for the link, but it was one of the two I was already looking at.

   I think I found the fly in the ointment, though!!  After studying 

 the second 2N3904

 diagram from "ON Semiconductor", I see they use a different pin number 

 designation.  AH HA!!

 They call Fairchild's pin#1, their pin#3, etc, etc.

   Must be trying to confuse the weak-minded....

   In any event, I think I got it whipped!  Thanks, Dave.

 Mike Welch

 *

 *

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

mdnanwelch7(at)hotmail.co
Guest

Posted: Tue Sep 21, 2010 5:02 pm Post subject: NPN & PNP pin ID

  

 	  Quote: 	
		   You can do basic checking with your ohmmeter to easily find the base, 

 > Dick Tasker
	




 Dick,

  

   You are right about checking each brand's data sheet, but I do think I've got

 them figured out properly, tho.

   Just for kicks, I think I'll check them out with my multimeter.  It does have that

 function.

  

 Mike Welch

 		 	   		    [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Sep 21, 2010 5:55 pm Post subject: NPN & PNP pin ID

At 06:17 PM 9/21/2010, you wrote:

 	  Quote: 	
		  

<retasker(at)optonline.net>



There are, in fact, versions with different pin-outs.  Not just a 

different pin numbering scheme, but BCE connected to different 

physical pin locations.  I got bit by this once upon a time.



The only way to know exactly what you have is to know who made the 

part (specific part number) and look at their data sheet.



You can do basic checking with your ohmmeter to easily find the 

base, but you would need a transistor tester to ID the E vs C.  Some 

multi-meters have this capability built-in.


	


    Hmmmm . . . we used many thousands of 2N3904/06 devices

    in products I designed 40 years ago and I don't

    think I ever got a problem-flag raised by production

    stating that a batch of devices wouldn't fit the board

    layout.



    If you look at the Fairchild package drawing at:



http://www.fairchildsemi.com/products/analog/pdf/to92_dim.pdf



    you'll note that it gives 3 pinout configurations for

    both bipolar devices like the 3904 and field effect

    transistors. Note also that three different BiP-Fet

    pairs are labeled TO-92, TO-94 and TO-96. If you

    were dealing with some house-numbered device and

    trying to sort out interchangeability with any another

    device, yes, you might find some pin-out differences

    between two otherwise identical looking devices. But the

    2N series numbers are JEDEC (Joint Electronic Devices

    Council) numbers. To build a REAL 2N3904 it had better

    be in a TO-92 configuration package to pass muster

    with folks who make a living at tracking such things.



    If you have electro-whizzies in hand marked 2N3904

    then it's a pretty good bet that the pinouts conform

    with the bi-polar column of the TO-92 column in the

    above data sheet. Looking at the flat side with

    leads down they run left to right EBC



    That's the way my drawer full of 3904/3906 devices

    are configured too.

   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum