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transistor questions

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darklordchris

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could someone help me out a bit with equivalent transistors ?
I think that getting the right ones is one of the problems i've been having. is their a standard? how do i know whats what? are their going to be minor differences that are going to mess up my radio circuits?

also more importantly does anyone know if the NTE 2N4401 527 is equivalent to the bc548?
 
Each transistor number has a datasheet that details many of its max allowed voltages, max allowed current and its current gain. Also its max frequency is listed.

The 2N4401 has a max allowed collector-emitter voltage of 40V and the BC548 has only 30V.
The max allowed collector current for the 2N4401 is 600mA and the BC548 is only 100mA.
The current gain of a 2N4401 at a collector current of 10mA is typically 195 and the BC548 is about 250.
The max oscillator frequency for the 2N4401 is 250MHz and the BC548 is 150MHz.

So you can see that the two transistors are quite different.

EDIT: Their pins also are in a different layout.
 
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is their some kind of criteria for picking one out of the search results?

Cross Reference Search Results 18 matches returned
 
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Odd..I got 18 results and the page says on it, "Replace part" "with NTE part"
and several variations of BC548 are listed.
I think you did something wrong with the search page.
 
The bc548 is electrically similar to a 2N3904.
 
I don't think NTE makes anything. They buy other manufacturer's transistors, stamp their own part number and raise the price 4 times higher.
It is a rip-off.

The store in your town sell them because then their profit is 4 times higher than if they sold "normal" parts.
 
Odd..I got 18 results and the page says on it, "Replace part" "with NTE part"
and several variations of BC548 are listed.
I think you did something wrong with the search page.

no..it just did that for some reason when i posted the link.....i got the 18 matches to
 
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I don't think NTE makes anything. They buy other manufacturer's transistors, stamp their own part number and raise the price 4 times higher.
It is a rip-off.

The store in your town sell them because then their profit is 4 times higher than if they sold "normal" parts.

not really sure. i think the diode from the other project was about $1.50 if that helps
 
Your welcome. :rolleyes:
 
Your welcome. :rolleyes:

thanks.... no,......i'm just trying to wrap my head around all this....it seems really annoying to figure out the equivalents

how did you figure out what the best one was? or rather what is the criteria for picking the best equivalent part?
 
I worked as a components engineer for a few years, so it is just experience on my part. It takes time but you will get the hang of it :)

Side note, it takes a lot of searching, pain in the you know what.
 
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