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Prakash Chandra Nayak Jul 16, 2008, 11:52pm EDT Reply - Quote - Report Abuse
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What is the Equivalent of C945 Transistor


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Joshua Marius, LeThe Jul 17, 2008, 02:42am EDT Reply - Quote - Report Abuse
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>> Re: Transistor Equivalent


You may need to contact a local electronics store.

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

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john albrich Jul 17, 2008, 06:09pm EDT Reply - Quote - Report Abuse
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Edited: Jul 17, 2008, 06:52pm EDT

 
>> Re: Transistor Equivalent
"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

john albrich Jul 17, 2008, 06:33pm EDT Reply - Quote - Report Abuse
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>> Re: Transistor Equivalent
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)

Prakash Chandra Nayak Jul 18, 2008, 03:20am EDT Reply - Quote - Report Abuse
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>> Re: Transistor Equivalent
Thanks Very much.

Thanks And Regards
PRAKASH

Dublin_Gunner Jul 18, 2008, 04:58am EDT Reply - Quote - Report Abuse
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Edited: Jul 18, 2008, 05:06am EDT

 
>> Re: Transistor Equivalent
john albrich said:
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)



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)


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john albrich Jul 20, 2008, 01:22am EDT Reply - Quote - Report Abuse
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>> Re: Transistor Equivalent
DublinGunner said:
...Just checking 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)


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.

Ian Shelby Jun 06, 2009, 03:08pm EDT Reply - Quote - Report Abuse
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>> Re: Transistor Equivalent
It is either 2SC945 or BC945

Most likely 2SC945 (Manufacturers often drop the first two characters)

faisaltp tp Sep 26, 2010, 04:07pm EDT Reply - Quote - Report Abuse
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>> Re: Transistor Equivalent
11n60

john albrich Sep 26, 2010, 07:10pm EDT Reply - Quote - Report Abuse
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Edited: Sep 26, 2010, 08:50pm EDT

 
>> Re: Transistor Equivalent
faisaltp tp said:
11n60

Well, the thread is quite old, but even so...the 11n60 being a MOSFET switch I would not consider it an "equivalent"...especially if the original circuit was using the transistor in a mode that was not just providing an "on/off" switching capability. While the 11n60 is used in high-power on/off switching apps it might not work as a suitable replacement in a specific circuit designed for bi-polars even when dozens of different general purpose NPN bipolar transistors would work fine. The 11n60 is a LOT of overkill (e.g. ~100-200 milli-Watts v. the 11n60's 100+ Watts), and about 10x the price.


Some might find interesting some basics about using very simple digital on/off circuits...one for MOSFETs and one for NPN bipolar transistors...

Simple On/Off "Switch" Using MOSFET
http://www.electronics-tutorials.ws/transistor/tran_7.html

Simple On/Off "Switch" Using NPN Bipolar
http://www.electronics-tutorials.ws/transistor/tran_4.html

Ian Shelby Sep 27, 2010, 12:34pm EDT Reply - Quote - Report Abuse
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>> Re: Transistor Equivalent C945
C945 refers to 2SC945


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