I'll respectfully disagree.

Harold


On Mon, 12 Nov 2001 07:58:13 +0000 Mike Blakey
<mike.blakey@BAESYSTEMS.COM> writes:
> The power used and dissipated by the voltage regulator is NOT
> calculated that way.
> the power dissipated by the device is approx. = (Vin-Vout) *
> quiescent current and
> NOT load current. Check the data sheets!
>
>
>
>
>
> haroldhallikainen@JUNO.COM on 09/11/2001 18:44:56
> Please respond to PICLIST@MITVMA.MIT.EDU@INTERNET@wtgw
>
> To:     PICLIST@MITVMA.MIT.EDU@INTERNET@wtgw
> cc:
> Paper Mail:
> Subject:        Re: [EE]: PIC overheating a 7805 !
>
>                    *** WARNING ***
>
> This mail has originated outside your organization,
> either from an external partner or the Global Internet.
>      Keep this in mind if you answer this message.
>
>
>         24V is a bit high! Calculate out the power dissipation
> (24V-5V)*LoadCurrent. Take this (in watts) and multiply by the
> rating of
> your heat sink in degrees C/ watt. This should give temperature rise
> from
> ambient.
>         Another thing to watch for is oscillating regulators, which
> get hot.
> Check the output on a scope and make sure you've got DC without a
> bunch
> of RF.
>         Finally, consider a switching regulator. The inefficiency of
> using a
> linear regulator to go from 24V down to 5V is pretty impressive.
>
> Harold
>
>
> FCC Rules Online at http://hallikainen.com/FccRules
> Lighting control for theatre and television at
> http://www.dovesystems.com
>
> ________________________________________________________________
> GET INTERNET ACCESS FROM JUNO!
> Juno offers FREE or PREMIUM Internet access for less!
> Join Juno today!  For your FREE software, visit:
> http://dl.www.juno.com/get/web/.
>
> --
> http://www.piclist.com hint: The list server can filter out
> subtopics
> (like ads or off topics) for you. See http://www.piclist.com/#topics
>
>
>
>
>
>
>
>
> ********************************************************************
> This email and any attachments are confidential to the intended
> recipient and may also be privileged. If you are not the intended
> recipient please delete it from your system and notify the sender.
> You should not copy it or use it for any purpose nor disclose or
> distribute its contents to any other person.
> ********************************************************************
>
> --
> http://www.piclist.com hint: To leave the PICList
> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>
>

FCC Rules Online at http://hallikainen.com/FccRules
Lighting control for theatre and television at http://www.dovesystems.com

________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
http://dl.www.juno.com/get/web/.

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu