Is it possible that the same transistor has different pinout in different units

[hunted22]

Hello all..

First of all, I gotta say that I'm a noob, so keep that in mind and take it easy on me.

1. I need to know how to figure out Base, Emitter and Collector of a transistor using a multimeter.

2. Is it possible that the same transistor has different pinout in different units? cuz I bought this transistor "2N 3906" and tested it to find the base pin (which is as far as my knowledge goes regarding finding trans pinout) I found that the base is on the side, but when I checked online, I found that this transistor's base is the middle pin.

Thanks in advance.

 

[audioguru]

You should look at a manufacturer's datasheet to see which pin is which. Here it is:

 

[Nigel Goodwin]

Different manufacturers often have different pinouts for the same device number, as AG says, check the datasheet for the manufacturer you have.

 

[hunted22]

thank you for responding..

I have no idea on this transistor's manufacturer.. I guess the only way is to figure out the pinout myself..

Anyone can direct me to link where this thing is simplified?? all of my search results were way over my head.

 

[Nigel Goodwin]

thank you for responding..

I have no idea on this transistor's manufacturer.. I guess the only way is to figure out the pinout myself..

Anyone can direct me to link where this thing is simplified?? all of my search results were way over my head.

It's easy to find the base, base to emitter and base to collector read on a meter as two diodes. Identifying collector and emitter isn't so easy.

 

[Mosaic]

Usually it depends on the transistor package.

The TO92 package shown will always have the same arrangement for all BJT transistors. I have not seen other packages for the 2n3906 unless they are SMD.

Metal case transistors (TO5, TO3) etc have a metal tab near the collector. Just look up the package for the transistor u have and u can figure it out. You don't really need the specific datasheet then.

 

[audioguru]

Transistors with prefixes of 2N, BC, 2SC and 2SD are registered and must all have the same pinout and spec's for a certain part number.
Jfets have different pinouts because they are symmetrical and their source and drain can be reversed with no change in operation.

 

[vlad777]

In my modest experience base to emitter shows higher number on the multimer (which should be voltage)
then base to collector. The difference is small AND you should NOT hold transistor in your hand
because it slowly heats up and voltages drop enough to confuse you.

Also collector (or drain in fets) is most likely connected to case if it has metal portion, and with TO220
and similar it's usually middle pin.

 

[Jaguarjoe]

Metal case transistors (TO5, TO3) etc have a metal tab near the collector.

The tab identifies the emitter, not the collector.

 

[hunted22]

Transistors with prefixes of 2N, BC, 2SC and 2SD are registered and must all have the same pinout and spec's for a certain part number.
Jfets have different pinouts because they are symmetrical and their source and drain can be reversed with no change in operation.

Then how come I get a different base pin testing this 2N transistor?? do you mean its defective? I ve got of and they both give the same reading.

 

[audioguru]

Some Oriental transistors are fakes. Inside they use crumpled tin foil instead of a transistor's chip.
Your fake transistor doesn't even have a reputable manufacturer's logo on it. I bet you bought it on e-bay.

 

[crutschow]

Metal case transistors (TO5, TO3) etc have a metal tab near the collector. Just look up the package for the transistor u have and u can figure it out. You don't really need the specific datasheet then.

Metal cases for small-signal transistor such as TO-5 and TO-18 have a metal tab by the emitter. The TO-3 is a diamond-shaped power transistor case and has no tab.

 

[Roff]

The TO92 package shown will always have the same arrangement for all BJT transistors.

This is definitely not true.As an example, look at MPSH10.

 

[audioguru]

The TO92 package shown will always have the same arrangement for all BJT transistors.

Absolutely NOT!
All if not most 2Nxxxx transistors have EBC pins. All if not most BCxxx transistors have CBE pins. Oriental 2SCxxxx transistors frequently have the C as the middle pin. They all have the same TO-92 package.

 

[Roff]

Absolutely NOT!
All if not most 2Nxxxx transistors have EBC pins. All if not most BCxxx transistors have CBE pins. Oriental 2SCxxxx transistors frequently have the C as the middle pin. They all have the same TO-92 package.

And some TO-92 RF transistors, such as the MPSH10, have BEC pinout. I believe this is to minimize C-B capacitance, and to have the emitter act as a shield in the case of common emitter amplifiers.

 

[Mosaic]

sorry about the incorrect post.......haven't played with transistor variety much in a few years. Mostly 2n2222,2n3906/4 and TIP31/42 etc.
I withdraw it.