7343Re: NSLU2 using 7805s and a 12V battery
- May 3, 2008Hi
Must admit I'm somewhat rusty on my electronics theory. Regulators
are rated with suitable heatsinks fitted.They are very derated
without heatsinks. Various problems here - the regulator has to
disapate a 7V drop as well as the actual current drawn. There is a
way to use a 78xx regulator with an external transistor to boost
See page 22 of the datasheet below for a 7805 which shows a typical
A large Watt rated resistor between the 12V and the input to the
regulator may also help, but regulation might become an issue as the
volt drop across the resistor would increase as current increased.
--- In firstname.lastname@example.org, efil vasers <efilvasers@...>
>an old wifi
> I'm trying to run my NSLU2 (with a 1GB flash drive, connected to
> router) from a 12 volt SLA rechargeable battery (5Ah) using 7805voltage
> regulators.amps), and
> So far, I've tried a few different regulators (rated 1 or 1.5
> when I turn the NSLU2 on, after about 30 seconds, the regulatorsare too hot
> to touch and soon shut themselves down.immediately
> I'm not sure what the problem is.
> Just to try, I connected it with a single 7805 (1 amp), which
> shut itself off.up to 3
> I connected the regulators in parallel with each other to provide
> amps (more than the NSLU2 power supply), so I figured that Iwouldn't need
> heatsinks for them. Am I wrong, or is my NSLU2 just behavingstrangely?
> How many people out there have tried this?and the
> (For those wondering, this is for a robotics project for school,
> NSLU2 is running Debian)7805s-and-a-12V-battery-tp17030363p17030363.html
> View this message in context: http://www.nabble.com/NSLU2-using-
> Sent from the Nslu2 - General mailing list archive at Nabble.com.
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