[TenTec] Noise from Fans

[Mike Bryce]

The lm317 drives the fan(s) so up to the current rating of the 317 or about an amp. 

Most small box (muffin) fans draw considerably less current. 

The idea is to get the fan up to speed, then slow it down. 

Sometimes by slowing a fan down too much, (diodes or whatever)  it won't start reliability. 

This circuit solves that problem. 

Mike wb8vge

Sent from my iPhone

> On Mar 7, 2014, at 3:24 PM, Bill  NY9H <ny9h at arrl.net> wrote:
> 
> how many fans / how many amps...
> are you limited to current capacity of the lm317 , or does that drive some of the transistors????
> 
> 
>