Article View: sci.electronics
Article #10105Re: 12 to 9 volts dc
From: Jon Panek
Date: Tue, 12 Feb 1991 16:03
Date: Tue, 12 Feb 1991 16:03
19 lines
1270 bytes
1270 bytes
I'd have to agree... my Toyota Celica voltage meter regularly floats around 15-16V while the engine's running. A constant voltage drop setup, like the in-line zener, or the chain of Si diodes is not a very robust solution. The simple solution is the 7809. Make sure the power rating on the '09 is enough to handle the expected dissipation: P = EI, where E is the voltage *difference* between the engine (use 15-18V) and the output of the device (9V) -- this gives E of ~9V. I is the current needed by the discman. This gives you power in watts. Note that devices higher than about 0.5W require proper heat-sinking to achieve their max ratings... I sure wouldn't want to risk *my* discman on a junkbox solution... Good luck! Jonathan Panek Hewlett-Packard, Andover Division panek@hp-and.an.hp.com (508) 687-1501
Technical Details
Message-ID:
<13650002@hp-and.HP.COM>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!elroy.jpl.nasa.gov!sdd.hp.com!hplabs!hpda!hpwala!hp-and!panekReferences:
<1991Feb10.220719.17078@cbnewsl.att.com>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!elroy.jpl.nasa.gov!sdd.hp.com!hplabs!hpda!hpwala!hp-and!panek From: panek@hp-and.HP.COM (Jon Panek) Newsgroups: sci.electronics Subject: Re: 12 to 9 volts dc Message-ID: <13650002@hp-and.HP.COM> Date: 12 Feb 91 16:03:30 GMT References: <1991Feb10.220719.17078@cbnewsl.att.com> Organization: HP Andover Division (Massachusetts) Lines: 19