12 volt automotive fan speed controller

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mark krawczuk

Posted: Sun Nov 25, 2007 1:21 am

Guest

hi, i am after a basic type schematic to controll the speed of a 12 volt
dc automotive cabin fan .

seems to be a bit of a problem in these saab`s.

any schematic using a mj11032 or mj11016 darlington would be good. if
not any electronic speed controll schematic will be fine.
the original darlington is rated at about 25 amp , seems a bit excessive....
these darlingtons i have are rated at 30 and 50 amp.

thanks, mark k

Eric Sears

Posted: Tue Nov 27, 2007 5:57 pm

Guest

On Sun, 25 Nov 2007 15:43:20 +1030, "mark krawczuk"
<krawczuk@adam.com.au> wrote:

Quote:

I have found many circuits that way.
There are many of what you are looking for that use a 555 timer and a
20+amp FET - but I see no reason why the MJ darlingtons you mention
could not be made to work. I use the Dick Smith circuit (which used to
be found in the back of the annual catalogue) - I think both the Aus
and NZ catalogues were much the same.
There are some other circuits which use an op amp as a comparator, but
all are based on a variable ratio on/off switching.

Best wishes with finding what you want.

Eric Sears.

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