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Old 3rd Jun 2019, 10:49 pm   #1
60 oldjohn
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Default SOT23, 8A code (SMD)

I have a transistor marked 8A possibly BA. It did not work in the circuit, turned out it was a PNP transistor not NPN as expected. Sorry for the photo quality but if you zoom in on the first photo you may just be able to make out the markings. Actually the second picture is not to bad and it looks like BA Any ideas to what the part may be?


John.
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Old 3rd Jun 2019, 10:58 pm   #2
MrBungle
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Default Re: SOT23, 8A code (SMD)

Have a look in the code book here - usually helpful: http://www.marsport.org.uk/smd/mainframe.htm

Also might be a letter on the base of it as well.
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Old 4th Jun 2019, 11:00 am   #3
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Default Re: SOT23, 8A code (SMD)

Looks like an MMBT1015.


Bog standard BC857 should work (or BC557 if there's room to bodge one in).
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Old 4th Jun 2019, 11:07 am   #4
60 oldjohn
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Default Re: SOT23, 8A code (SMD)

Quote:
Originally Posted by MrBungle View Post

Also might be a letter on the base of it as well.

Had not thought of that, but I can not see anything on base.


I have had a look on various lists, but nothing that is PNP listed that I can see which this one is.


John.

Thanks Chris, I think you are right, this is the pack they came in.
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Old 4th Jun 2019, 11:21 am   #5
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Default Re: SOT23, 8A code (SMD)

Odd.

The code book linked by Mr. B. gives one of the BA possibilities as the MMBT1015 I mentioned.

Edit:

Lots of "crossed in the post" going on here

Nothing quite like time delay in a loop to cause instability!
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Old 4th Jun 2019, 11:32 am   #6
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Default Re: SOT23, 8A code (SMD)

Roger's code book is usually quite reliable.

The package label looks like a 'tick one' list as it covers both PNP and NPN types. It's a bit of a general purpose small transistor hit-list.

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Old 4th Jun 2019, 12:26 pm   #7
Norman Raeburn
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Default Re: SOT23, 8A code (SMD)

What I usually do in this instance is look around the board for another marked the same and check the connections/polarity etc with a meter. Worst case scenario is to remove another carefully to perform tests. Norman
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Old 4th Jun 2019, 9:22 pm   #8
60 oldjohn
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Default Re: SOT23, 8A code (SMD)

Quote:
Originally Posted by Radio Wrangler View Post
Roger's code book is usually quite reliable.

The package label looks like a 'tick one' list as it covers both PNP and NPN types. It's a bit of a general purpose small transistor hit-list.

David

No, all the 18 transistors were in one pack in strips of ten. I am trying to identify all 18 and ticking them off on the label shown as in most cases it is only a partial number. I made a mistake with the 8A as I had identify it as a NPN, which I needed for a circuit I was making. The circuit did not work until I changed it for another numbered NPN then discovered the 8A was a PNP. Sorry if I have gone on a bit.

John.
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Old 7th Jun 2019, 1:20 am   #9
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Default Re: SOT23, 8A code (SMD)

Seems like the SMD version of the (2S)A1015 in that case.
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