Demo Time – Bang, Flash! – there goes the power strip…


It's two hours before my monster embedded session at Tech Days "innovez avec les technologies embarquées Microsoft" (Embedded Innovation at Microsoft, or something like that) - this session is part of the "Innovation" track at Tech Days.

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The session is all about demos, .NET MicroFramework (Hello World and "Invaders"), CE 6.0 (Picture Frame using an Enfora CellCore device), XPE (File Based Write Filter, Custom Shell, USB 2.0 Boot), and WEPOS (build a POS solution without all of the hardware).

I wanted to get into the room early to test out the video and networking - all of the hardware I have with me uses USA power adapters (everything is happy with 110v - 240v), so I brought my trusty straight-through power strip from my office - something weird happened in the conference room - the power strip went bang, there was a flash, followed by an interesting smell of ozone, and then everything stopped working...

The event team didn't have any plug adapters to convert the USA plugs to European plugs, so I needed to go running to see if any of the local stores had any adapters - unfortunately not... Thankfully my hotel is very close to the conference center and they had an ample supply of adapters at only 10 Euro's a pop (an absolute bargain!) - so it looks like the demos may be back on again... - we shall see...

If all goes well, and all the hardware still works then we will try to capture a video of some of the demos later today.

- Mike

Comments (1)
  1. Jay Daniel says:

    Mike,

     For what it’s worth, the pop you heard from your power strip isn’t all that strange.  Cheap power strips (nearly all of them) use devices called MOVs (metal-oxide-varistors) to suppress surges.  Basically, they act like an open-circuit when the voltage is below some threshold, and then shift over to looking like a short-circuit (across the line) if the voltage spikes too high.  Usually the clamping voltage is selected for the expected voltage plus some reserve factor.  For short bursts, the MOVs can hold up to a few pulses.  For longer surges, they just self-sacrifice.

     When they fail, it’s really a 50-50 shot as to whether they "fail open" or "fail closed."  If they fail open, you’ll have a power strip that appears ok, but has lost all surge suppression capability.  If they fail closed, however (what happened in your case), they remain shorted across the line and make the strip useless.  If you look at the bottom of the strip, I’m betting you’ll see a voltage rating right there with the current rating.  This is your clue that "straight-thru" is a misleading description of these things. 🙂

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