OHM's Law and LED's

...and don't forget that resistance often drops with an increase in temperature (usually as the components get hot!). ;)

M

The obvious thing to me is that if a light is running at a higher voltage and current than before, it's simply using more power! (And is probably brighter!).

The fact is your power output is not the same. Clearly the power output is going up, thus both voltage and current can increase without breaking Ohms law.

If you could control the power usage of the LED, then yes only voltage OR current could increase, but that's not the case.

Quote:

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Originally Posted by camel_landy

...and don't forget that resistance often drops with an increase in temperature (usually as the components get hot!). ;)

M

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Only if it's a negative temperature coefficient (NTC) resistance like a temp sender or a LED. Normal resistors (and filament globes) go up in resistance with higher temps.

Mr Whippy, the problem with the stated wattage of a bulb/lamp is it's only a nominal rating, real wattage consumption depends entirely on the measured current and voltage at any instant.