Using diodes to limit fan speed?

scoob8000

2[H]4U
Joined
May 4, 2002
Messages
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I've read many articles and plans about using diodes to drop voltage to control fans.

Everything I've seen refrences the 1n4001 which is rated at 1amp and provides about a .75v drop.

So how would I handle loads greater then 1amp? (Thinking WC pump)

Would wiring two in parallel do the trick, or is there a better diode to use?
 
Yeah, I've been doing the 7 volt trick for awhile. I'll usually rig a DPDT switch up to run my fans at either 7 or 12 volts.

Here's what got me hooked on diodes:
http://www.cpemma.co.uk/sdiodes.html

And to answer my original question, you can run them in parallel to increase current capacity. I decided to go with a 1N5400 diode rated at 3amps instead.
 
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