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- From: ryoung@pollux.svale.hp.com (Roderick Young)
- Date: Mon, 9 Nov 1992 21:56:25 GMT
- Subject: Re: 12 V -> 3V, 0.6 A
- Message-ID: <5150062@pollux.svale.hp.com>
- Organization: Hewlett Packard CPCD, Sunnyvale CA
- Path: sparky!uunet!cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sdd.hp.com!scd.hp.com!hpscdm!hplextra!hpcss01!hpergfg2!pollux!ryoung
- Newsgroups: sci.electronics
- References: <1992Nov7.141550.538@ludd.luth.se>
- Lines: 10
-
- Warning on using LM317 to drop 12V to 3V at 600mA...
-
- You car battery could put out as much as 14-15V sometimes. Let's say 13V.
- That means a (13-3 = 10V) drop across this linear regulator. At 600 mA,
- that's 6 WATTS. It might work, if you use the TO-3 version, and a very
- good heat sink. You might consider putting a 8-ohm, 10-watt resistor
- in series with the LM317 input to disspate some of the power.
-
- I actually used a (surface mount) LM317 to drop 12V to 5V, as less current
- than you specify. The chip got so hot, it melted its own solder!
-