Xref: utzoo comp.sys.ibm.pc.hardware:9372 comp.sys.amiga.hardware:9814 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!sunic!dkuug!ruc.dk!holck From: holck@gorm.ruc.dk (Jesper Holck) Newsgroups: comp.sys.ibm.pc.hardware,comp.sys.amiga.hardware Subject: Re: TURN COMPUTER OFF OR LEAVE ON? Message-ID: <1991Jun4.082135.15082@gorm.ruc.dk> Date: 4 Jun 91 08:21:35 GMT References: <1991May24.033650.15836@cbnewsc.att.com> <20114@rsiatl.Dixie.Com> <1991May25.151636.679@monu0.cc.monash.edu.au> <1991Jun3.194555.3525@newserve.cc.binghamton.edu> <1991Jun3.212159.27391@jato.jpl.nasa.gov> Organization: Roskilde University, Denmark Lines: 33 jdickson@jato.jpl.nasa.gov (Jeff Dickson) writes: > I've heard that it is less expensive to run flourescent lighting >24 hrs/day. This is because more current is used to "juice" the ballast >when its first powered, than is used during its operation. Many office >buildings do not reguarly cycle their flourescent lighting for this purpose. >I would imagine that a CRT is similiar. A CRT tube basically behaves as a >large capacitor. This means that when power is first applied, an abnormal >current surge is required to "charge" it up. I have a SUN display terminal >here at work. It's left on all the time. It, however, has a screen saver >type thing that blackens the screen and displays a varying pattern of blocks. >This saves the phosper from being "burned" and also cuts down on the amount >of heat it produces. Perhaps someone with more insight could elaborate on >this further. I think you have got some things wrong ... The reason that some companies leave their fluorescent lightning on is because turning the lightning on stresses the tubes a little, so they won't last so long, not because of the minimimal extra power consumption turning them on. Obviously they can't in a few seconds use electricity comparable to hours of use. However, even the companies rely on some misunderstandings. It is estimated that the cost of turning a fluorescent tube off and on again (due to the reduced life time of the tube) is comparable to 1/2 to 1 hours cost of leaving the tube on (due to the increased use of electricity). So the general "rule" for fluorescent tubes is: If you are certain that you will need the light from the tube again within an hour, leave it on, otherwise turn it off. I don't know if this also goes for computers though .... Jesper