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Comment: Re:so... (Score 1) 260

by serbanp (#47534195) Attached to: Google Offers a Million Bucks For a Better Inverter

The input is DC so there is no need for low frequency input decoupling

Unfortunately, that's not true. The output is AC and the input-referred current will reflect it, i.e. will be quite high when the output reaches its highest (340V). Since the input source has an equivalent internal resistance of 10Ohm and would droop too much, some bulk capacitance is needed to provide these 120Hz current surges.

I agree with you that the design revolves around the placement of power components (capacitors, inductor, power switches and some sort of heatsinking), then the control circuitry be crammed in the spaces between them.

Comment: Re:so... (Score 1) 260

by serbanp (#47524895) Attached to: Google Offers a Million Bucks For a Better Inverter

Having read the actual spec, I realized that my question was stupid. Input voltage is 450V, therefore the inverter is just a full-bridge DC/DC converter

The challenge is actually perfectly doable, with the only difficult points being the size of the switching inductor and the input bulk (most likely tantalum) and output filtering (must be ceramic) capacitors. IOW, the winner will be the one with the best connections to component manufacturers.

Comment: Re:it depends on what "skilled worker" means. (Score 1) 401

by serbanp (#47402095) Attached to: No Shortage In Tech Workers, Advocacy Groups Say

However, there are about 600,000 H1B workers in the USA. How many of these do you believe have the skills only found in comp-sci grad programs, or more to the point, how many of those don't have and don't need grad school comp-sci skills?

One thing I never understood is why so many posters on /. believe that Comp-Sci is the only highly technical field that matters. H1B visa holders are many times technically-educated people who have nothing to do with programming (i.e. Chemistry, Materials Physics, EE etc).

The Sun does not revolve around IT, so why are we suggesting it does?

Comment: this guy is out of his mind (Score 3, Insightful) 228

by serbanp (#47364045) Attached to: Nathan Myhrvold's Recipe For a Better Oven

Not only it's not obvious what "better" means when baking is involved, but he's showing his Microsoft roots here, stupid "improvements" that make the whole system break so much easier.

It's a known fact that most "modern" residential ovens, the ones with displays, lots of buttons to set baking programs etc, should never use the self-clean cycle. The thermal insulation is not good enough to protect the electronics (a.k.a. control board) and the oven fails, typically after a high-heat cycle (the self-clean reaches 700-800*F). This is equally true for GE and Whirlpool as well as for Viking and Ilve.

Adding more electronics to a hot environment is asking for more and expensive trouble.

Commercial appliances are better built though, are they Myhrvold's target? In any case, his post is just a petulant rant showing overkill application of technology, just because "he can". Zapping mosquitoes with laser beams sounds more realistic...

If you have to ask how much it is, you can't afford it.

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