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how does voltage affect leds and charging batteries? Answered

assuming amps are the same how would a different voltage affect powering an led or charging a battery and im assuming there's an upper limit and if so, r u able to find it out without a data sheet (since leds pretty much never have any markings on them)?

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V-Man737Best Answer (author)2009-10-16

LEDs have a sort of activation voltage below which they won't shine, anda max voltage above which their magic smoke will escape. This range istypically between 3 and 5 volts, although without any resistors, even 4volts could significantly lower their life.

With batteries, how the voltage affects the charging battery reallydepends on the material it's made of. For instance, you couldconceivably charge a 1.5v NiCD battery directly using a car battery, butif you tried that with a LiPo or Li-ion battery, you'd probably losebody parts.
Generally, in charging batteries, the charging voltage should be equalto or slightly higher than the nominal voltage of the battery you are charging.

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frollard (author)2009-10-16

Use the water analogy.

Voltage is pressure (how much potential energy electrons have to get form a to b)
Amperage is current (total flow)

If amperage stays the same, then think of how much water comes out a pressure washer.  Not much, similar to a garden hose (on low).  A garden hose and a pressure washer have the same 'amperage' or flowrate.  The pressure washer shoots the water out with incredible force, capable of shooting longer distance and vapourising the water as it comes out.  The garden hose...doesn't.

Now look at your electricity.  An led takes advantage of a specific 'pressure' (voltage) of electricity to excite a semiconductor enough for it to shoot off photons.  Too little pressure and you get no light.  Too much pressure and you blast the hell out of the semiconductor and it becomes a notconductor.

Similarly with batteries:  Like a balloon, they have a capacity, and a pressure.  (amperage (total) and voltage).  If you apply an amount of pressure, it will fill to that pressure.  Too much, and you'll blow up both the balloon and the battery.  If you apply more amps, the balloon will fill faster, same with battery, but only at the right pressure.

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frollard (author)Molten Boron2009-10-16

I got a kick out of writing that...Congratulations.  You are the first to point it out :D  I love it when that happens as planned!

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Molten Boron (author)frollard2009-10-17

I thought at first you were talking about some clever way to make a new component type! LOL!

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Sandisk1duo (author)2009-10-15

leds: depends on the color of the LED


Batteries: depends on the battery chemistry

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