What is the Equivalent of C945 Transistor

You may need to contact a local electronics store.

Here's the specs: http://www.futurlec.com/Transistors/C945.shtml

"C945" may be insufficient information to determine an accurate replacement device. The ID printed on components can be misleading, and is sometimes a shortened version of all the info needed for an accurate cross-reference. For example, for the exact same transistor ID, a suffix might be required to identify the correct "pin-out" of the transistor as that can vary...yet for something as simple as space limitations the suffix may not be printed on the actual case of the device.

Here are some possibilities: (enter your "c945" in the search field as needed)
http://nte01.nteinc.com/nte%5CNTExRefSemiProd.nsf
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=13763...words=c945
http://www.mouser.com/Search/Refine.aspx


Might be replaceable by:
(Check specs to be sure. Prefixes and suffixes can make a difference)
MPQ3904
2N3904

Other data that can help provide a more accurate cross-reference (at least make sure it's same application or form-factor):

How is it used? Is it by any chance used in a low-power voltage inverter, or power regulation?

Very helpful: What type of case does it have? For example, is it TO-3, TO-92, TO-5, TO-220, surface-mount, etc.? Is it plastic or metal? Is it mounted on a heat-sink? Here are some pics: (look toward the bottom of this file)
http://sound.westhost.com/trans.htm


edit-fix URL reference that didn't work

Also, in certain applications, you don't need an exact match. It can in fact be very far from being an exact match and still function properly and reliably.

For example, in a switching transistor power inverter circuit, you can often get by with a transistor that merely matches whether it's PNP or NPN, and then meets just the minimum voltage and power dissipation requirements. Beta isn't necessarily critical. In fact sometimes you can even use a transistor with a totally different form-factor (e.g. a TO-220 vs. TO-3 case)

Thanks Very much.

Thanks And Regards
PRAKASH

john albrich said:


As I have done many times while building power regulation / amplification circuits from schematics.

If you're not dealing with ultra accurate inupt / output voltages/currents etc, its very unlikely that you would need an exact match, the mere fact that the transister switches when its supposed to will usually be enough.

**edit

Justchecking the specs on that transistor, I'd imagine pretty much any general purpose NPN would do fine. Shouldn't be too difficult to find a general purpose NPN, even with the same TO-92 package type, I can get them for about 50c (even 18c)

DublinGunner said:

I agree completely. The main concern I had above was that he might not be accurately IDing the transistor. But, if he is, a general replacement should work fine, and should be dirt cheap and easy to find.

If anyone asks you for more than Dublin quoted, they're definitely ripping you off!

BTW, you can probably scavenge a replacement from any spare hybrid or "pin-in-hole" circuit board you have...an old printer board, CD drive, etc.

If you want help on how to tell a PNP from an NPN using a volt-ohmmeter, just let us know.