Is there a solid way to ID SMD ICs? Short of search engines / LLMs

[Hix]

I wondered if there are any good resources for helping to identify SMD components? I would like to try and understand more about some circuit boards and knowing what some of the ICs are would help by being able to download datasheets.
For example I have a board with a couple of what I assume to be transistors which are marked only 2Gt. Google / Gemini / Co-Pilot seem to generate a lot of conflicting info and none of it seems to be solid.
I just wondered if there was some kind of specialist site or resource that could assist in IDing components?

[squadchannel]

I never use AI.

I determine it based on the marking's shape, size, font, position, etc.
also search Google for things like “<marking> ic <package>” to find images. I use sites searchable by marking too, but most Chinese semiconductors aren't listed there.
board's designator is also helpful, and I sometimes decipher the traces to imagine what kind of circuit it is.

It's mostly based on experience.

good website I recently found.
http://eric1688.com/
http://www.maoye-smd.com/index.asp

When it comes to three-digit codes ending with a lowercase letter (especially "t"), wouldn't that be Nexperia?
Nexperia's SOT-23 package should have a two-digit lot code (date code?) written vertically next to the marking.
BC850C?

[KhronX]

For example I have a board with a couple of what I assume to be transistors which are marked only 2Gt. Google / Gemini / Co-Pilot seem to generate a lot of conflicting info and none of it seems to be solid.

The package also matters - the same marking could indicate different part numbers, depending on the package.

If your example of "2Gt" is on SOT323 packages, that would point towards BC850CW - the lowercase letter is usually a fab indicator, and not part of the marking "as such".
Source: https://www.s-manuals.com/smd/2g

One other comprehensive-ish page with SMD markings is https://smd.yooneed.one/

There used to be chip.tomsk.ru, that was THE MOST comprehensive SMD marking database i had seen, but that went down some years ago. It's still accessible (at least somewhat) on archive.org, but functionality there is so-and-so...

[Hix]

Thanks very much. I'll bookmark those.
It is amazing what archive.org can recover from the past. It's a brilliant resource.
Appreciate your reply, thanks again.

[tycz]

I've found the easiest way is to search Taobao with the package type and marking. It's common for merchants to put the IC marking in the title.

[KE5FX]

I wondered if there are any good resources for helping to identify SMD components? I would like to try and understand more about some circuit boards and knowing what some of the ICs are would help by being able to download datasheets.
For example I have a board with a couple of what I assume to be transistors which are marked only 2Gt. Google / Gemini / Co-Pilot seem to generate a lot of conflicting info and none of it seems to be solid.
I just wondered if there was some kind of specialist site or resource that could assist in IDing components?

Got any photos that show the part with the markings?  That may work better than just asking the LLM to identify a code with a few characters.  They aren't tuned for that kind of input.

Also, don't waste time on free chatbots.  Post the photo here and I'll feed it to the big-kahuna models.

[Hix]

Here are a couple that spring to mind

[KE5FX]

I didn't have time to review the answers right away, but here are the reports from the research-enabled models:

https://gemini.google.com/share/4def61b366fe

https://chatgpt.com/share/6966aeef-3ff0-800b-aa27-b9ed90237a6f (32 minutes of cogitating, that's a new record for my prompts!) 

[Buriedcode]

If theres a reasonable marking - I google that. If not, I narrow it down by context and then package, and finally pinout.  For example, if its an 8 pin SOIC, with pins 5-8 joined, and 1-3, its most likely a MOSFET.  Fat traces usually mean power.  SOT23  usually have just two characters, and goolging that bings up loads of results, but you can tell by the circuit its in whether its PNP/P channel, or NPN, or even single/dual diodes.

Sometimes it doesn't really matter - if a circuit has a 3 pin device driving a MOSFET that enables power to something, it doesn't always matter what the exact part number of the transistor is, just that its switching.

These days there are an increasing number of "black" devices that dont' really have an online footprint - switching regulators for LED lighting, odd micros etc.. can be annoying but often these are in pretty cheap devices that just aren't worth repairing. Stuff that we usually think are worth repairing are either vintage stuff = which greatly increases the likelihood of finding datasheets, or expensive high end gear, where the designers haven't had to race to the bottom, so use what they are comfortable usuing and what works best in circuit.  Either way, tends to be pretty straightforward to find data on most devices.

[Hix]

So, are these educational LLMs or similar? How do you access research modes?
Appreciate your time, thanks.

[KE5FX]

So, are these educational LLMs or similar? How do you access research modes?
Appreciate your time, thanks.

They are just the "Pro Thinking/Reasoning/whatever" versions of the same models available on the various LLM chat pages for free.  The free models are designed to return results fast, even at the cost of making stuff up or missing obvious issues.  A paid account lets you select versions of the model that will do extensive web searches (and optionally cite their sources, most of which will usually actually exist.) 

These models will spend much more time and tokens on chain-of-thought analysis than the free versions will.  Another benefit is that if they don't know something, can't access the needed information, or can't make sense of it, they are more likely to admit it rather than hallucinate something.  They can be considered a better-Google-than-Google, in that they will regularly find answers where normal human users will fail.

They are also better at generating code as well as analyzing and debugging it. 

Drawback is that they cost money.  Need to be on their $100-$200/month plans if you don't want to regularly run out of tokens in the middle of a coding session, or if you don't want to be subject to significant rate limits on the highest-performing models.  For the time being I have subscriptions to Claude, Gemini, and GPT5, but I will eventually need to narrow that down to one or two at the most. 

[Hix]

Really appreciate your effort there. Even if they aren't sport on, it gives me enough to go with that I can at least try to learn what these boards are doing with some better guidance than I had before.
Thanks very much KE5FX