I recently purchased a 'grab bag' of components which included a bunch of transistors. Most of the transistors are what I think of as a typical transistor, black case, flat on one side. Many of these transistors have no markings on them at all. Others say things like "NTCMP S3706" or "NTC P N4916". Is there a reasonable way to learn more information about the specifications for these transistors?
Thanks.
James Howe
The first thing I would try is typing the numbers on the marked devices into Google. If that doesn't work try truncating the part number as the last few characters could just be a batch code, date code of package options. If you recognise the manufacturer you could go to their website and see if you can find the part there.
Here are the websites of some transistor manufacturers:
For the unmarked devices it could be very difficult. There are many electronic devices which have three legs so these parts may not even be transistors.
Good luck.
Gareth.
============================= You can tell if its pnp or npn with an ohmmeter.... if you know the pinout.... red on base, black on emitter showing some lo ohms... its npn
For the ones with numbers, type em into google... mps3706 sounds like a motorola (or On semiconductor) number, 2N4916 might be a vaild number...
Radio Shack has a handly little (and inexpensive) tester that will classify common small signal transisters by type (NPN, PNP) and flag the base and collector leads. Part # 22-330. Not sure that this is in their current catalog but you might be able to find a store with one.
Also, many general-purpose multimeters have a socket that accepts a transistor and that then reads out hfe (more or less). It helps to know the type and CBE order, though, so even with one of these the little RS gadget is helpful.
NTC is a Taiwanese semiconductor manufacturer; Nanya Technology
PN4916 is originally from Fairchild, in your case is probably OEM-sourced implementation from NTC too. Datasheet is here:
It all boils down to exposure and experience. Just like everybody knows what brands of PC exist in the market. You'll soon learn what are the dominant seminconductor manufacturers are there...
In a male or female voice? That's a big clue.
Besides those other good suggestions, electronics parts stores (real ones) have cross-reference guides. They gave me one (the NTE book) a long time ago. Note, the specs of the original and replacement might not be an exact match, but hey, it's a grab bag :)
Maybe Bainsville Electronics in b'more (or someone like that) has a cross-ref search on their web-site.
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