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Comment: Re:Essentially yes, you do (Score 1) 323

by SuperKendall (#49796611) Attached to: The Tricky Road Ahead For Android Gets Even Trickier

Hahahaha more powerful than having the source code,

Do you never tire of beclouding yourself?? I suppose not...
Well for the MENTALLY SLOW HERE I WILL EXPLAIN IT REAL CLEAR LIKE.

On iOS, you can easily change the OS AND APPLICATIONS.

On Google you can only change easily what you have source for, which is the OS - not applications.

So I'm pretty sure even the most addle-braned can understand one is greater than two...

I leave any response to your own fevered mind, I shall not read it.

Comment: Re:Even if you go DC, stay at 120V (Score 1) 502

Everything from your wall switches to your wires will cause you never ending problems.

Mechanical wall switches are still rated for DC. Houses USED to be wired for DC a lot. You only have to replace the stuff that was designed after AC was pervasive and wasn't engineered to handle DC.

(I forgot to mention that you'll also have to replace the light dimmers, too, along with most other electronic, rather than mechanical, switches. They usually use a current-zero-crossing turnoff device, and DC won't cross zero unless you force it to do so.)

Even if you replace your wall switches and outlets, your wires will degrade over time and develop holes and other blemishes that will cause a fire.

No they won't - unless they're wet (in which case you have bigger problems than galvanic corrosion). Electromigration at the current densities involved in house wiring is not an issue, nor is insulation breakdown. The wires and fittings will be just fine.

Comment: Re:Even if you go DC, stay at 120V (Score 1) 502

(DANG this stupid touchpad... )

An "inverter", by definition, actually has alternating voltage as a substantial output, or at least somewhere in the circuitry. A switching regulator has a cycling voltage, but it isn't an AC output, or even an AC intermediate.

But they're very similar.

(Also: I was going to mention, above, that the current supplied through the pull-down (or clamp-at-ground) switch is where the extra output current comes from, compensating for the lowered voltage with higher current for similar amounts of power. If the switches, inductors, capacitors, and wiring were all ideal, the driver and sensor circuitry didn't eat any power, and no energy was radiated away as radio noise, efficiency would be 100%.)

Comment: Re:Even if you go DC, stay at 120V (Score 1) 502

A down-stepping DC-DC converter is not an inverter?

Nope. But the pieces of the implementations are similar enough in function that it's close.

A typical DC/DC down converter involves two switches, an inductor, and both input and output filter capacitors, plus control circuitry to sense the output voltage and time the switches. (There may also be a VERY small resistor in series with the inductor to sample the output current if current regulation is necessary, but it's omitted for high efficiency if that's not an issue.) One end of the inductor is hooked to the output cap, the other through the switches to the input cap and to ground.

The pull-up switch is always active (typically a transistor). The control circuitry turns it on and the current in the inductor ramps up, charging the output capacitor at an increasing rate. After a while the pull-up switch is turned off and the pull down switch is turned on. The current through the inductor ramps down, but before it goes through a stop and reverses the pull-up switch is turned back on and the pull-down turned off. The pull-down switch may be a diode, which switches on as needed automatically, but for high efficiency it's usually another transistor, because it has a lower voltage drop and thus is more efficient.

The control circuitry varies the percent of pull-up versus pull-down time to keep the average output voltage at the desired level. The frequency may be controlled or may be allowed to vary somewhat.

So the waveform in the inductor is a sawtooth, and the current never reverses. An "inverter" by definition,

Comment: Large change with app permissions (Score 4, Insightful) 69

They talk about how it's a stability release, but if you are going to compile your application with the newer dev tools you are going to have to do some work adapting to the iOS style permission model.

I'm really glad to see Android adopted this model, the previous model made no sense from any standpoint - it was worse for the users, and worse for security. Now that Android will ask for permission when you actually want to use some protected resource, they can make a way more informed choice if they should allow it or not - and on the fly decide an app can access some things and not others (say allowing Contacts but not location).

It's just a shame the older style permission model will be supported for some time to come, as it greatly eases the ability of spyware to operate on Android.

Comment: Essentially yes, you do (Score 0) 323

by SuperKendall (#49792249) Attached to: The Tricky Road Ahead For Android Gets Even Trickier

Oh? So you have the source code? Snicker snort.

Your ignorance is no laughing matter.

Because of how easy Objective-C is to pull compilable headers, and how easy it is to extend any class and override any method (swizzling), you have everything you need to change ANY app or system process even though you don't have all the original source code. It's lots more powerful than just having source code for the OS and not apps...

Its' really too bad you can't understand how much more powerful this is to actual hackers.

Comment: Re:Even if you go DC, stay at 120V (Score 4, Interesting) 502

(Continuing after brushing the touchpad posted it for me. B-b) ... equipment at that voltage. (Small systems are often 12V due to the availability of 12V appliances.)

But back to inverters:

Current inverter and switching regulator (they're pretty much the same stuff) technology is SO efficient that large PC boards in computing and networking equipment may run the power through as many as THREE DC-DC converters, because you lose less power to heat as losses in the inverters than you would to resistance running it a few inches through a printed circuit board power plane.

So the '"20-40% loss" number seems to me to be utterly bogus.

(Consider this: A Tesla automobile IS AC motors driven by inverters from batteries. A horsepower is almost exactly 750 watts. If they had 20-40% losses in the inverters, how do you keep the car from being on fire after a jackrabbit start? Let alone recover enough power on braking to reuse on acceleration to make a substantial difference?) If ANYBODY knows how to handle inverters it's Tesla. B-) )

Comment: Even if you go DC, stay at 120V (Score 4, Interesting) 502

This is strange. "20 to 40% power loss" seems to be an awfully poor inverter; existing inverters are 4-8 % loss.

Rather than rewire every house in America, wouldn't it make more sense to just design better inverters?

Or just run at 120V DC, as renewable energy systems did (and occasionally still do) before so many appliances were AC-only that it made sense to use an inverter.

Dropping voltage means you have to replace the copper wiring with MUCH HEAVIER wiring - by a square law - to carry a given amount of power with the same loss - and thus wiring heating inside the walls, where it can set the house of fire.

Switching to 120V just means using DC-capable appliances and replacing the breakers (DC is harder to interrupt) and must-be-GFCI outlets (normal GFCI devices use a transformer to sense unbalanced load).

The 48V standard was about having a voltage that was low enough that touching it was typically survivable, so working on or near it is (relatively) safe. The boundary between the hard part and the easy, "low-voltage", part of the electrical code is 50V (BECAUSE of phone companies B-) ). Medium power (>1KW) home Renewable Energy systems tend to be at 48V so much of the wiring falls under the easier part of the code, and because of the availability of

You cannot have a science without measurement. -- R. W. Hamming

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