Homebrew PCBs

2009/12/24 saposoft <sapoliste@...>:
> Well Well this is fantastic ... care to share the schematic ?
>
> --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan <stefan_trethan@...> wrote:
>>
>> I used a thermistor, and a BC547 transisor in place of the ua741.
>> ICs are way too expensive to waste on a thermostat ;-)

I need to keep a heatsink, its about 3 inches by 2 inches, in a switch
mode psu, cool,  about 35degC would be fine, I have a fan that easily
manages the task, but is noisy if on all the time, so was thinking of
driving the fan via a thermostat circuit so I designed one but havnt
built it yet, and before you say thats a waste of a 741, mine is based
on a 18f2550 !

Why, because I can understand the thing, I can use the a/d converter
to read the thermistor, then get the controller to output PWM to
control the fan speed, I'd never get it working if i went with analog
electronics now!

I'm ashamed to admit i've probably forgotton so much analog that i
know less of it now than when i first got interested in my teens.