amperage question

Discussion in 'Electronic Basics' started by Jeremy, Apr 8, 2006.

1. JeremyGuest

I have a cpu fan which is rated 12v dc 0.06A can I run it in my truck or
will it burn out?

2. w2aewGuest

Jeremy,
You should be able to run it OK. The voltage in your truck will be
closer to 13.8V when running, and nearer to 12.5V when off. Most 12Vdc
fans can operate at these slightly higher voltages without a problem.
To be absolutely sure, you can check the manufacturer's specs. If you
don't know how to do that, post the manufacturer and part number here,
and someone here will look it up and let you know for sure. The
manufacturer and part number are located on the label in the center of
the fan motor.

3. Tom BiasiGuest

As long as your truck is 12 Volts.

4. ptwGuest

CPU fan can work from as low as 8 volts, so a few volts above 12 v can
be too much. I would definitely stick a voltage regulator.

(+) ------- [7812] ---------+
| |
| [FAN]
| |
(-) -----------+------------+

[7812] is the part number for regulator. An example is L7812CV.

5. Michael A. TerrellGuest

The 7812 needs 14 to 15 volts on the input to regulate.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

6. ptwGuest

Well, it works for me in practice. See for yourself:

http://img323.imageshack.us/img323/3856/img07445ua.jpg
http://img323.imageshack.us/img323/6028/img07460fj.jpg

7. ehsjrGuest

The regulator is obviously not regulating, in your
photos. He could accomplish the same thing a whole
lot cheaper with a resistor or three diodes.

Ed

8. James ThompsonGuest

If the voltage is less then 12 volts out then the 7812 is simply a resistor
dropping the voltage.
Why even use it in the first place?

9. James ThompsonGuest

It will be happy there...

10. Rich GriseGuest

I'd also, on the off-chance that's it a brushless DC motor, put about
a transzorb across the input, like a 16V or so, and probably a hash
choke (that's just an inductor that can handle the DC current without
saturating.)

Automotive electric systems are hell on electronics.

Good Luck!
Rich

11. redbellyGuest

Because when the voltage goes much above 12V, the regulator will go
into regulate-mode and protect the fan.

Mark