If I hook a 12volt 12watt light up to a 9v battery.. Am I still

>>8521981
P=VI

>>8522062
That doesn't answer my question

>>8522110
U=R*I

>>8522177
That doesn't answer my question either.

>>8521981
3/4?

mfw /sci/ can't prove it's 3/4 with a simple linear function

>>8521981
"12 watt" is its rated operating point, i.e. the point beyond which the lightbulb should not exceed for a long period of time lest the diode junction draw too much current and burn out. It is not a magical quantity to which the LED must adhere at all times.

The amount of amps the diode will draw depends on its I-V characteristic. It's not as simple as P = VI.

>>8522254
because it is not linear you high school tard.
Filament heats up tremendously, as a consequence the resistance changes. You need to know the resistance vs temp curve also the heat dissipation capabilities at each temperature.
In case of LED you need constant current source, cause heating up of semiconductors lower their resistance.

>>8522263
doesn't matter it's still linear. assume an IV ratio of anything you want. just write the function.

>>8522272
They don't heat up or cool enough with a difference of 3 volts to significantly change amps. You can round to the nearest hundredth.

>he can't write a simple linear function

>>8522272
>it's not linear
loool

>>8522308
sure, you can do whatever
>>8522314
https://en.wikipedia.org/wiki/Ohm's_law#Temperature_effects

>>8522329
I told you you could round. Prove it's within 100mA of 750mA.

>he can't do it

>>8522329
amperage would be adjusted after the function with the temp coefficient. the relationship is linear with any ohmic circuit. you should be able to write the function.

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>>8522342
>>8522353
I can do it, but why should I?
To prove it to you? To do your homework?
Nah, think what you want, I don't care.
Umad?

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>>8522304
>doesn't matter it's still linear

What part of [math] I_S \bigg( e^{\frac{V_D}{nV_T}} - 1 \bigg) [/math] is linear to you, exactly?

Frankly, if you hooked up a 9 V or 12 V battery across an LED with a thermal voltage of 1.8 V, you would fucking nuke it from the EXPONENTIAL current draw after the diode was turned on.

>>8522342
From wikipedia: assuming tungsten filament of length 0.58 m, radius 0.000023 m, the current through the filament is indeed 0.7837 A. Of course 1.) the page said it was for a 60 W bulb, not a 12 W, and 2.) 12 W is not nearly enough to get the filament to its 2500 K or so temperature for emittance, from the Stefan-Boltzmann law. That is why I assumed an LED.

>>8522353
>the relationship is linear with any ohmic circuit
ahahaha fuck off and don't come back until you've taken at least a 200-level course in EE