Music LED Sync?

for the circuit in the pic can I use the transitor listed here  instead of TIP31, SMD LED Strip instead of the 4 LEDs, and can I power it with an ATX Power Supply as it also has 12v DC output????
Thanks in Advance.....

Picture of Music LED Sync?
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I can't see the transistor you're interested in in the link, but here you won't need high power handling, you just need a high gain - shoot for Hfe >>500.
adarshnarsaria (author)  steveastrouk4 years ago
Do you mean forward current transfer ratio (hFE)???
Yes.
adarshnarsaria (author)  steveastrouk4 years ago
Will a forward current transfer ratio (hFE) of min: 20 will do???
I SAID
"you just need a high gain - shoot for Hfe >>500"
adarshnarsaria (author)  steveastrouk4 years ago
HFe >> 500 means less than 500 (>> = Less Than)?????
VERY (hence >>) much GREATER THAN.
BASIC maths.
adarshnarsaria (author)  steveastrouk4 years ago
well but tip 31 itself has hfe of min 20???
Then how come the world is syncing their LEDs to music with those TIP31s ???
Its a dumb choice. Just because lots of people use it doesn;t make it less of a dumb choice.
adarshnarsaria (author)  steveastrouk4 years ago
well, will these do??
http://alltransistors.com/crsearch.php?mat=Si&struct=NPN&pc=40&ucb=80&uce=40&ueb=5&ic=3&tj=150&ft=3&cc=0&hfe=500&caps=TO220
adarshnarsaria (author)  steveastrouk4 years ago
okay i got that and I am really very sorry for being stupid....
iceng4 years ago
You need a series resistor with the LEDs

this is how.
a gain.gif
iceng iceng4 years ago
Or a better circuit
aa gain.GIF
adarshnarsaria (author)  iceng4 years ago