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3-Terminal Regulator question

3075 Views 16 Replies 4 Participants Last post by  micromind
i have a charger that I use for my PSP that is 300mA and 4.5v.

The PSP is 5v 2A

this charger isn't the real charger for the PSP, it just happens to fit and it works fine (just takes longer).

im making a charger out of small 1 watt solar panels and using a +5v 1A 3T regulator. So would it be ok to use a +5v 1A charger for the 5v 2A? That wont damage my PSP right? charging under the specs?

also, will it damage a 5v 1a 3 terminal regulator putting 2.5 amps into it from the solar panels? Or is it specifically made to reduce amperage as well?

many thanks
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A power supply maintains a set voltage, upto the rated current. The device (the load) is what dictates how much current is needed.

If your PSP draws, say, 300ma, you can connect any power supply that is more than that with no problems... a load is a load, it cannot be forced to draw more than it needs.

current is kinda like horsepower, your car might be RATED at 300HP, but that doesn't mean when you're backing out of the driveway you're using all 300HP... you just need a car to be RATED at enough horsepower to get the job's there when you need it. How much is being used depends on the LOAD (ie if grandma is driving or the 16yo)

Therefore, you simply build a device that provides the proper voltage, 5VDC, and make sure the whole project is rated UPTO 300ma or whatever your PSP needs... this all is so don't worry about it.

official datasheet for your ship:

10V for instance would fry your PSP, so you have to regulate it down to 5V with the LM7805 chip.

Well, the more you regulate it down to, the more heat you will dissipate and that LM7805 will burn the **** outta your fingers, so attach it to some sort of heatsink, the tab on your chip happens to be ground so you can just screw it down to a metal project box and it will absord enough heat to operate fine.
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