Got SmartBook G138 Yesterday - Need Advice!

Got a SmartBook G138 (UK Model) from 'emulti' yesterday!

Looks good, but he wouldn't sell it to me with the UK AC adapter...so looking for one here in Silicone Valley....

Went down the street yesterday to large electronics supply house and they had lots of adapters in their catalog. However, just my luck the 2 they thought would work, were out of stock until mid-Sept!!

So need to keep looking....

Meanwhile, the tech guy there said that since the SmartBook label says that it takes 12V/2A that as long as I get an adapter that's 2A or more, the SmartBook would draw the power it needs. He said to avoid getting one that's less than 2A as that would cause problems.

Does that sound correct?

If so, does it matter how much more than 2 Amps it is? For example if it's 3A or 5A, is that OK???

Just want to make sure before I mess up my new toy...

Thanks for any input!

Mark

Mark, you can't "force" a device to use too much current from the adaptor - anything over 2A will be fine. Check the voltage, and also check the polarity (centre positive or centre negative).

Hp changed from centre negative to centre positive between the HP200lx and the 320lx. That was a most appreciated move

Good luck!

(Where did you get the smartbook from???)

If you push a 5A current through a device expecting 2A... surely Chiark it'd frazzle itself...
For a sensitive circuit in a 2A device... a step up to 5A would cream it

dun have to worry much about the current for a power supply, as long as its more than what is required from the device.

Voltage just need to be the specs +-1/2v or so. Someone was saying that most devices has voltage regulators so it will get the right voltage inside.

O.o OK, best explain this one to me then.
Hypothetical - My device has a 3A fuse in it, and I supply a 5A current. Why doesn't the fuse blow?

The point is you can't "push" current. Your wall socket can put 30A out at 240V into your 13A fused device, which will only draw how much it can... Otherwise your fuse board would be melting right now.

It's like having a large engine and only pootling around - the potential (pun not intended) is there, but it's not being used. Fuel is available, but not being used.

warning: gross simplification/lies to children follow: 1 amp means that one coulomb of "electic charge" flows per second. You can't force more through - it's like trying to force water through a restriction without speeding it up*


Cheers,
Nick.

* - yes, I know this is a "lie to children", but it works for the purpose of explaining why anything above 2A ain't a problem.

You're not giving it 5A: you're making up to 5A available to it. It draws what it needs to draw.

Simply put (more lies to children), a device has a "resistance", which dictates how much work the device will do. Resistance (R)= Voltage (V)/ Current (I) and is fixed for a device (more lies, but assume its true for simplicity).

Power = Current (I)* Voltage (V). For an analogy, imagine that voltage is the speed of a lorry, and current is the amount of stuff the lorry is carrying.

If you've got a device that consumes 25W, at 12V it'll consume just over 2A. Giving it a 5A power supply won't make it a 60W device, because you've not changed the device's resistance, or ability to do work.

If you try to power a device needing 2A at 12V (24W) from a 10W power supply, it won't work... But if you try to power a 2A at 12V (24W) device from a 100W power supply, it will.

Yes, yes, I remember now. I'm swapping applied logic on voltage onto amperage again.

I think it's more PC to call voltage 'Electric Pressure' these days. You wouldn't think it, but I did ace the three sciences.

hehe ... as explained above. Remember, its power supply, not power driver! ... so as mentioned, the power supply current ratings are for maximum load current that the load can draw and that it can supply.

Voltage on the other hand is different.

C:Amie's brain drain for the day. Hey, at least it'll clarify it for those who aren't as dippy as I am

more on Voltages and Current this new OT thread.

Let's resume the original request on this thread!

ArchiMark,

!! First make sure this !!
The AC adapter that comes with the Smartbook (if it's like mine) should take 230V AC input. But in North America, our homes only get 110V to 120V. Logically it would not cause harm, as the voltage is too low instead of too high, but still it won't work and I would advise not to try to connect it directly.

Personally I use a voltage converter. It is literally a brick, but since I already have one around I just used it. It also accepts the UK plug just fine. I do not know how much one costs nowadays, just shop around and make sure it's maximum current is enough. BTW, if it doesn't show current but only the power rating, just remember 1 Watt = 1 Amp X 1 Volt.

If you want to use a replacement adapter instead, as you seem to be pursuing, then I think the replies before me have explaned the precautions quite well (despite C:Amie's err, diversion...). Just one thing to add, if you use an adapter that cannot supply enough current, it may burn itself out as your device tries to draw that much. Happens all the time in our PC world

In any case, good luck finding a solution, and welcome to the exclusive club of Smartbook owner(s) on the board! It gets lonely sometimes

P.S. All that confusion about the current thing reminded me of my arguement with my "engineer" brother. He kept saying if the bulb's power rating exceeds "max" power rating of the light (usually marked on a sticker), the bulb would blow. I told him the lamp's internal wiring would overheat instead (potentially causing a fire), and the bulb would be fine, and he just wouldn't believe me... justice anyone?

Not sure of the ac adapter for smartbook, but it must be stated as 110~220v, ie auto switching or auto-sensing adapter in order to be used in either 110 or 220 (or 120/240) AC power supplies. Otherwise, it will most likely *BLOW* a fuse or a coil. If its a fuse, then just replace it and get a step up/down adapter, if its a coil, its moot. You've been warned.

Seems to me the thing to do is simply go on eBay and buy a used HP laptop adapter...most all of the are 12V and about 3amp rated.... Solder an appropriate connector on instead of the laptop connector and that's it.

Rich

Wow! Thanks a lot guys for all the sage and erudite responses to my question!!



Meanwhile, managed to get my hands on a 12V/2A AC power adapter today, so far it's working fine and battery is almost all charged up!

Couldn't wait, so I did turn on SmartBook briefly to see that it works.. which it does!!

As takwu has said before, it has VERY NICE display!

So takwu you're in good company now!

takwu, FWIW, the emulti guys in UK would only sell me the SmartBook without the UK AC power adapter for the reasons you alluded to...hence my original post....

Very nice guys to deal with though and I received package much faster than I expected....

Now to get some PIM software, etc on it...right, takwu??

Thanks again to everyone for their input!

Mark