Fan Timer issues

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Thread Starter


Joined Sep 29, 2011
Looking at theis from a purely electrical standpoint. This circuit can be used to shut a computer cooling fan off 10 min after shutdown.

Need some help on an off delay fan controller I am building for an electronic fan. The goal was to have the fan run for 10 min after the 12v timer start input is shut off, then break the circuit.

I drew up this schematic and built a working prototype, and it works perfect on the bench. 10 min +/- 10 sec. However, upon installing my first build i discovered that any other loads on the circuit will cause my circuit to reset and break the connection prematurely. I tried integrating a 12v voltage regulator into the input, but the issue still remains. Even on the bench now, if add the presence of a light bulb to the circuit, it resets.



Joined Jul 17, 2007
Your other thread on this topic:
...was locked because it is clearly in direct violation of the forums' Terms of Service.

We can't look at it from a purely electrical standpoint, as the rules in the Terms of Service are pretty explicit.

You may not like that rule, approve of it, whatever - but that rule is set in stone, and has to be followed.

I don't make the rules - I just follow them. I urge you to do the same.


Joined Nov 25, 2009
@David G

This thread is a direct violation of the AAC forum rules, Chapter 6, as seen here:
Therefore, this thread will be closed.

This is the second time you violate the forum rule. This isn't about the forum look. This is about actual responsibility towards its members. Please don't attempt to violate the rules again or there will be consequences.
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