Circuit question

Hmm, I really don't think a 914 is going hold under the stress!

Jamie

$.38 is quite expensive? What do you consider cheap? BTW, they're about a penny in bulk.

Those are signal diodes, not power diodes. As usual, Rich is full of it.

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Signal diodes also drop .6v, and Man-wai never has said how much current needs to go through the diodes.

So, what's with this personal hardon for me? You never miss a chance to throw a limp barb at me - have you got a man-crush that you're ashamed of?

Thanks, Rich

I think it's already regulated.

Um... what hurdle? If you were talking about overdrawing more than

720mA, NO NO NO!

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The USB hub has been modified to charge iPod and MP3 player.

I know how to read a resistor's value, but not a diode.

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Come on, focus focus! Focus on the circuit! :)

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NOW you tell us . . . . It is likely that both are designed to take 500mA when charging, possibly even more if they think you have connected their dedicated charging adapters.

We now know the PSU is under 1A so its not fit for purpose. ===========================================================

If you want to build a single device charging station with it, you could, but in that case you wouldn't need a hub . . .

Power diodes have a type number printed on them. It may not be the full number so one needs some experience to guess if it should for instance have 1N added in front, but you can usually identify them.

If not, find a different used diode, or guess their characteristics from the ratings of associated components in the circuit they were in.

Some signal diodes use coloured bands for their code, some use a printed number and some are just unidentifiable, but signal diodes are rarely worth salvaging.

If you hunt for diodes in the part of the circuit I suggested, and the fuse is over 3A they *WILL* have an adequate rating for this project.

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Ok. Then I plug in just one. :)

The hub has 4 USB ports, plus an input. It's still money! :)

Thanks. Let me find out whether a new one is cheap.

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it depends on the plug, (different sockets hare the pins arranged differently) but usually the inner conductor is positive and the outer is ground,

yes. resistive dividers only work when you need no current at all. the more current you need the more of an approximation they become. the higeger the resistance used the worse it gets.

For this reason they are unsuited for reducing power supply voltage except in a few special cases - like the timers in pop-up toasters.

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So I should use diode or regulators? Thanks.

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How about buying the right wall wart?

Don't wanna waste that Nokia AC adaptor!!! Could I?

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Use it as a fishing weight. That's it's best use.

You need to answer the question you were asked earlier. Is this a regulated supply. You cannot guess, you must

*know*. If it is regulated, then two 1N400X diodes, as was mentioned in a reply, will work for you. If it is not regulated, you must regulate it.

If you cannot, or will not, determine if the thing is a regulated supply, then just buy something suited to the task.

Ed

Could I use a multimeter to find out?

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Do you know how to use a multimeter?

Your adapter can deliver max 720 mA. So a 1A rated diode is sufficient. Google for: Diode 1A You find Fairchild 1N1007 cost $ 0.0265 when delivered on a production roll. In an electronic part shop it is a bit more. But any 1A or more rated diode is ok.

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Tell me what to do!!! :)

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