Simple Project Help Please!

Heres the deal: I have a set of old computer speakers and a pair of computer case fans that just happen to fit inside the speaker housings. What I want to do is utilize the existing power cable (input: 120V 60Hz 25W, output: 15V DC 800mA) to power the fans. The fans are both labeled "12V DC 0.2A" and I really just want to know: A) will running the fans at 15V damage them, and B) is there anyway I could control the fan speed?

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panic10 years ago
my point: A) 15V will NOT damage a 12V fan.But it is recommended use some device to fit the voltage.You can just put 3 diodes in series to reduce the voltage. B) Some kind of fans has a control-pin to adjust the speed.I think change the supply voltage will DO change the speed.
LasVegas panic10 years ago
Just put a potentiometer in series with the fans (in parallel) to adjust the speed. One end to the power, the other end and the center to the fans.
britishgecko31 (author)  panic10 years ago
Thanks, but just out of curiosity, why diodes (and why 3)? I thought those just limited the direction of the current? Why not a resistor(s)? And these fans are really old--functional, but old--no speed control pin. What kind of switch would I need to control the voltage?
5Volt10 years ago
Recycling computer speakers and fans into an operator cooler? Cool ! Pun intended. Make sure to take pictures and post the instructable. I'll like it. Oh, the diodes are good. Ciao
trebuchet0310 years ago
A) Probably will shorten their service life B) Sure - control the voltage :)