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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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3rd Jun 2019, 10:49 pm | #1 |
Dekatron
Join Date: Dec 2004
Location: East Yorkshire, UK.
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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. Last edited by 60 oldjohn; 3rd Jun 2019 at 11:06 pm. |
3rd Jun 2019, 10:58 pm | #2 |
Dekatron
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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. |
4th Jun 2019, 11:00 am | #3 |
Dekatron
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Location: Leominster, Herefordshire, UK.
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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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4th Jun 2019, 11:07 am | #4 |
Dekatron
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Re: SOT23, 8A code (SMD)
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. Last edited by 60 oldjohn; 4th Jun 2019 at 11:20 am. Reason: Added text and picture. |
4th Jun 2019, 11:21 am | #5 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
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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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4th Jun 2019, 11:32 am | #6 |
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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. David
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4th Jun 2019, 12:26 pm | #7 |
Heptode
Join Date: Feb 2008
Location: Leven, Fife, Scotland
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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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4th Jun 2019, 9:22 pm | #8 | |
Dekatron
Join Date: Dec 2004
Location: East Yorkshire, UK.
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Re: SOT23, 8A code (SMD)
Quote:
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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7th Jun 2019, 1:20 am | #9 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
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Re: SOT23, 8A code (SMD)
Seems like the SMD version of the (2S)A1015 in that case.
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