On 21/08/05, Nick <[EMAIL PROTECTED]> wrote: > On 8/21/05, Lee <[EMAIL PROTECTED]> wrote: > > > > >> One of the other suggestions I've seen but not tried is to use 12v > > >> fans but run them off the 5v supply so they spin slow and quiet. > > > > > Noooo.............. > > Don't try this at home folks!! Running 12V fans at 5V is dangerous, they > > have a habit of NOT starting reliably. > > It may start OK when the lids off, but may not when it's back under the > > TV... With possibly tragic results... > > Exactly. Fans may also not start reliably if you give them 7V (using > the 12V and 5V feeds) so sometimes leaving them on the 12V is the > best.
Generally, 7v is enough to start most fans. 5v would not be. However, the very best way to run fans at slow speeds would be to use a PWM circuit system, that way the fan motor always has 12v to turn it. The only disadvantage of PWM is a possible "growling", but that's generally only found at VERY low speeds, and isn't audible if the PWM Frequency is above 20khz. -- Robert "Anaerin" Johnston _______________________________________________ mythtv-users mailing list [EMAIL PROTECTED] http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
