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Comment Re:Surge protectors *must* be voltage specific (Score 1) 137

Obviously you do not have the EE understanding required. A 220V surge protector is typically designed to clamp at around 500V. From rectified 110V AC that gives you a 350V relative spike into the capacitors. From rectified 220V it is only 190V. A 110V surge protector is typically designed to clamp at around 330V. That is an 180V spike. If you cannot see that a 350V spike may be a bit more destructive than an 190V/180V one, and that in particular, the components in the device may only be dimensioned for a 200V spike or so as that is what to expect with surge protection done correctly, then you have no business being in this discussion. If you have to ask where these numbers come from, the same applies.

Incidentally, this is only one of the problems with a wrongly dimensioned surge protector. And yes, the surge voltage is relevant, as it influences dU/dt and the surge current. In actual fact, there is a surge model behind this and the surge voltage is only one factor. Also, surge protection devices do not do a perfect clamping, and have maximum ratings. If they are exceeded, the surge protector may short out, fail or even start to burn if not fitted with a thermal fuse. Incidentally, there is a maximum of surges a surge protector can clamp, depending on the surges and its ratings. After that, it needs replacement.

Why do incompetent morons always feel they are qualified to comment on advanced engineering they really do not understand? The Dunning-Kruger effect is strong on Slashdot.

Comment "Teach Yourself Programming in Ten Years" (Score 1) 158

"Teach Yourself Programming in Ten Years" by Peter Norvig (http://norvig.com/21-days.html) is still an excellent discussion on how long it will take to learn programming to a degree that is actually adequate to do professional-level work.

In addition, I expect that most people will never get beyond "fair", even with this amount of training and experience, just as most people will not become much better than "fair" at any other task, unless they have some real talent/potential/gift/deal-with-the-devil/etc. whether it be cooking, mathematics, or playing the harp. That is not to discourage people. "Fair" would be a huge improvements over the skill-level of many of the people that write software today. "Fair" is level on which you can depend on people to get regular stuff right and to know what is beyond their skills ans ask for help.

Of course, "fair" is also the level where the expected salary needs to be very reasonable (say, at least enough for a 4 people family to live in modest comfort off it) in order to make people go though the long process of becoming good at it. In particular the latter is lacking today.

Comment Re:Surge protectors *must* be voltage specific (Score 3, Interesting) 137

Indeed. Even when you have a 100-240V device connected to 110V, you must use an 110V surge protector. The problem is that while a 220V surge protector would clamp at a voltage the device can survive, it can only survive reliably if it has been running at 220V because of the way these devices are designed. They have a rectifier and filter capacitor. If the filter capacitor gets charged up from 110V by a surge clamped for 220V (which clamps at around 400...500V), the inrush-current will likely blow the last-ditch fuse in the device and may well damage other components.

So, sorry, what you want is not possible. You must get both.

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