Naked Science Forum
Non Life Sciences => Technology => Topic started by: Atomic-S on 11/08/2008 05:18:37
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The monitor here, when shut off, appears to be not fully shut off, but still have a small amount of power present. Because of other problems, I have been shutting it and other equipment off at the power strip at the end of each session. The question is, which handling leads to the longer service life of the monitor: shutting off each time only at the button (or through the automatic system), or shutting off at the wall each time?
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For all practical purposes it will make little difference to the life of a monitor whether it is on standby or switched off completely. The particular components that determine the "life" will almost certainly be in the off state in both cases. In theory, the few components that are dissipating power could have their life shortened by remaining on, but these will not be the limiting factor. I believe some older design CRT based TVs and monitors kept the tube cathode heaters on to give a rapid start-up, and this would shorten life, but I don't think any modern designs do this. You will save a small bit of electricity by switching them off and I think this is about the only real difference.
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A small amount of power consumption can be beneficial, under some circumstances. It can keep the damp out and also maintain the polarisation of electrolytic capacitors.
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I was also wondering about things like filaments in the CRT which I thought might be worn out faster by repeated cycling than by just letting them run. Or anything which might be subject to voltage surges on start-up that might give out sooner with frequent cycling. But are these parts in any case shut off regardless of what method one uses to shut the monitor off? If so it would make no difference. ??????
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Because of the drive to have low standby power, nearly everything is shut off, especially CRT cathode heaters. In any case I expect we are talking about LCD screens nowadays. On a TV the standby power just tends to keep alive the minimal circuits so that the remote control works or that the TV remembers which channel you were on, volume setting etc.
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Cathode heaters are much more robust, these days. They can warm up v. quickly without too much harm. CRT lifetime is effectively infinite - i.e longer than you can stand waiting to buy the latest telly.
EHT is, more or less, instantly available so, with the standby circuit (an IR detector and a MOS control circuit to turn on the 'mains' for the rest) the only current drain can be minuscule. Flash memory can be used for things like your own settings / channel etc..
With proper power supplies, which are a trivial thing these days, everything can be protected from excess Volts or Current at switch on.