[TenTec] Noise from Fans

[Steve Garwood]

How much?

Steve, N0CZV

Sent from my iPad

On Mar 7, 2014, at 12:37 PM, Mike Bryce <prosolar at sssnet.com> wrote:

> Guys,
> 
> I’ve designed a small circuit that will run the a dc fan at high speed for a dozen seconds then drop the speed down to as low as it will run.
> 
> That way, the fan is sure to start, no matter how much cat hair it’s sucked up, or the condition of the bearings. Once started, runs at full speed for a bit,  then it slows downs.
> 
> both the fast on and slow run speeds are adjustable.
> 
> input voltage may be either 6.3 v ac, 12 v ac, or 12-18 v dc.
> 
> The prototype pcbs should be here within a week or so.
> 
> The circuit is simple, four transistors, a LM317 and a few diodes.
> 
> 
> Mike, WB8VGE
> SunLight Energy Systems
> The Heathkit Shop
> http://www.theheathkitshop.com/
> J e e p
> o|||||||o 
> 
> A man with one clock knows what time it is. A man with two clocks is never sure. 
> 
> 
> 
> On Mar 7, 2014, at 12:16 PM, Rick - DJ0IP / NJ0IP <Rick at DJ0IP.de> wrote:
> 
>> A few diodes would be cheaper than lots of beer.
>> You don't even have to calculate much.
>> Just figure on 0.6v drop per resistor.
>> I buy these diodes generally 100 at a time.
>> They cost just a few pennies each in those quantities.
> 
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