How does a flashlight work?

[Delta_FHInX]

In an aluminum flashlight, how does the flashlight get powered? Does the body itslelf act as a conductor?

 

[soloco]

Yes

 

[Delta_FHInX]

If so, isn't copper a better conductor than aluminum? Why don't be see more alloys of copper bodies?

 

[Stanley]

I think aluminium is a better conductor for heat as well, compared to copper? I guess this is only true if it requires the heat to be dissipated from a powerful light source, e.g. a Lux Star or something? /ubbthreads/images/graemlins/icon3.gif (BTW can you tell I'm no electronics expert? /ubbthreads/images/graemlins/smile.gif)

 

[Delta_FHInX]

Would gold or silver work as better heat and electricity conductors? I know titanium is stronger than aluminum, so how would that work?

 

[14C]

Flashlights are AM
Lasers are FM

Some flashlights are AFM

/ubbthreads/images/graemlins/evilgrin07.gif /ubbthreads/images/graemlins/evilgrin07.gif /ubbthreads/images/graemlins/evilgrin07.gif

 

[gadget_lover]

You are right about copper conducting better. What makes that irrelevent is that the metal body of the light is the conductor. A typical flashlight needs a copper wire only 1/16 of an inch across to transport the power. If aluminium were 1/2 as good as copper (and it's much better tahn that), you'd still only need a wire that's twice the size. The more power, the thicker the wire needs to be.

The wire that feeds your whole house is only as big around as your thumb.

The body of the flash light's a HUGE hollow wire. It is like having more than 100 wires side by side, each big enough to carry all the power.

This explanation is simplified on purpose, but technically sound.

Daniel

 

[Delta_FHInX]

so whats stopping the battery from short circuiting everytime it comes in contact with water?

 

[bwaites]

Only one side of the equation (the negative side) comes in contact with the water. (Hopefully) If the positive side did also, it would short. Thats why water tight/waterproof lights are so important.

Bill

 

[Rothrandir]

aluminum is:
cheap
light
annodyzable
carries electricity well
conducts heat well
resistant
machines well

certain materials might to better in one or several areas, but aluminum does it all quite well.
other than perhaps novelty, aluminum is definately the best choice.

 

[darkzero]

As stated, yes copper is a better conductor than aluminum, electrically and thermally (not for sure). But copper is more expensive than aluminum and not to mention heavier. Isn't copper softer than aluminum too? I beleive most flashlights are made of alloys anyways for strength reasons and aren't 100% pure aluminum.

Just look at some copper vs. aluminum CPU heatsink reviews and you get a good idea of their thermal properties.

Copper may "absorb" heat faster/better than aluminum but it takes longer for the heat to "disapate" from copper than it would aluminum. I beleive copper also corrodes/oxidizes faster than aluminum too.

Please correct me if I'm wrong, I would like to know the facts too.

 

[jbrett14]

[ QUOTE ]
Delta_FHInX said:
so whats stopping the battery from short circuiting everytime it comes in contact with water?

[/ QUOTE ]

Resistance of water would not allow for a "short circuit" as you are thinking.



Daniel said it perfectly about why better conductivity is irrelevant for flashlights.

 

[Harrkev]

Plus, old copper is kind of nasty to handle. It tends to corrode. Yuk.

 

[zumlin]

[ QUOTE ]
Delta_FHInX said:
so whats stopping the battery from short circuiting everytime it comes in contact with water?

[/ QUOTE ]

Water (pure) is not really conductive, however, if you mix in a little bit of salt, it creates ionic bonds in the water itself and conducts electricity.

 

[Sub_Umbra]

[ QUOTE ]
darkzero:
Copper may "absorb" heat faster/better than aluminum but it takes longer for the heat to "disapate" from copper than it would aluminum.

[/ QUOTE ]

I think that's pretty much right. If you look inside a baseboard radiator in a house that has water heat you'll notice that the heat is transfered through copper to aluminum fins which actually put the heat into the air. Even though these units are around 85% convective, they are always sold and referred to as radient. Go figure.

 

[gadget_lover]

There was a new water pumping plant installed in a Colorado city 10 or so years ago that stopped working because the water was too pure. Water was acting as one of the conductors through non-conductive pipe. The short term solution was to add impurities to the water intake. Long term solution was to add proper wiring.

If your flashlight is full of water it will discharge the battery, usually in a very messy way.

Thanks for the comment, Jbrett14. I almost NEVER say anything 'perfectly", and when I do it's seldom noticed. /ubbthreads/images/graemlins/smile.gif

Daniel

 

[jayflash]

If water inside a flashlight causes the batteries to discharge might that not be due to it leaking into the cells after some length of time? Otherwise wouldn't the water have to be quite saline and have absorbed a lot of impurities from the aluminum?

Normally it takes over 50 volts to overcome tap water's resistance. At 3 - 9 volts for a flashlight, that water inside would have to be very conductive - no? /ubbthreads/images/graemlins/confused.gif

 

[Delta_FHInX]

ok, so how will titanium work?

 

[jbrett14]

[ QUOTE ]
jayflash said:
Normally it takes over 50 volts to overcome tap water's resistance.

[/ QUOTE ]

Which is when water and electricity start becoming dangerous. All material is conductive, with enough voltage. Even air itself is conductive at very high voltages. Water, though not super-conductive, does become dangerous when mixed with normal household voltages.

 

[NikolaTesla]

Iz this 4 REAL? Flashlights are all FM. Not AM.

NikolaTesla /ubbthreads/images/graemlins/thumbsdown.gif /ubbthreads/images/graemlins/naughty.gif /ubbthreads/images/graemlins/wink.gif

How iz it me UK LC100 don't short out then 100 feet near Davey Jones locker? Izat cuz itz Plastic? /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/sleepy.gif
?????????????????? I dunno!

An Arc lamp is the Spark that takes away the Dark--HID Forever!
Recent additions to My Lights: *** http://www.tjtech.org/gallery/NikolaTesla/Dscn3236