By Stefan Fassbinder / Published on Tue, 2009-03-31 12:29
Here you see what can be observed at the input terminals of the PC power supply, in the first row with the full load of both the PC being operated and the battery being charged simultaneously, in the second row with the PC alone when the battery is full.
When you shut the PC down the residual power intake is only more 0.8W. With the active power being as low as this it becomes obvious from the view of the curve as well as from the measured values that the reactive current from a filter capacitor now prevails the total current.
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By Stefan Fassbinder / Published on Fri, 2009-03-20 12:23
The gross energy consumption to get back the 150 Wh consumed before (see last week) is 200 Wh. Note that this latter figure includes all losses incurred by both the charger and the charge-discharge cycle of the batteries! So we are faced with a pretty good overall efficiency of the process being as high as 75%, and we can say that the gross power consumption of this portable PC when used off the line, including all charge-discharge and conversion losses, is between 11 W and barely 40 W. The battery operating time is between 5 and 18 hours.
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By Stefan Fassbinder / Published on Fri, 2009-02-06 16:03
Indeed there are PC power supplies on the market which do not have any fan built in at all! To achieve this, there are two options, both of which need to be employed fully to match this objective:
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By Stefan Fassbinder / Published on Fri, 2009-01-30 09:02
Last week we wondered why a PC power supply with “lower” losses needs 50% more airflow. Let us now decide that it’s just a sect’s belief, called “case modding” (at least in countries which don’t speak English – nearly all Google hits are in German). Let us decide what can be done to achieve what the “advanced fan speed control” was supposed to do but does not do. The solution is frighteningly simple.
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By Stefan Fassbinder / Published on Fri, 2009-01-23 21:13
Last week we wondered why a superb fan control heavily tries to cool a 17°C cold PC power supply with 17°C cold air. Here you see the package of last week's PC power unit, which promises a “higher” air flow and 60% noise reduction. 60% of what? I can tell you from a disappointing experience that the reference must have been said vacuum cleaner.
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By Stefan Fassbinder / Published on Fri, 2009-01-16 08:30
Obviously not a FAQ, but just taken as Gospel: PC power supply units need fresh air – the more, the better. This has been right from the very beginning when a PC used only around 40 W. There are and have been other power electronic devices around with a much higher input or throughput rating, respectively, but which do without any fans at all. Now, is it necessary for PC power units to be so poorly designed that they have excessive losses, or is it just a culture – a newfangled fashion – that a PC needs to have as many fans as possible to show off its performance?
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By Hans De Keulenaer / Published on Tue, 2007-11-13 14:01
Technology
Computers, used everywhere, have become the keystone of all working activities, from calculations to farming!
Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers (85-100 W for a typical one). Notebooks, on the other hand, consume as little as 15 W and do not require the use of an Uninterruptible Power Supply (UPS), thanks to batteries.
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By Stefan Fassbinder / Published on Fri, 2007-04-13 13:45
How to cope with harmonics from a PC power supply? This is one cheap and very sturdy solution: A reactor in series with the input side provides a substantial mitigation of the harmonic level, though not a perfect one, of course, but enough to comply with the requirements of EN 61000-3-2. The reactor cannot be designed with a much greater inductance because then the voltage drop would be too great and the behaviour of the PC would become inductive.
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