[guitarman531]

Long story...but it's for a school project...

What kind of battery/capacitor(?) setup would I need to power a 40w light bulb ('normal' lighting fixture size) for a few minutes?

I would prefer to use capacitors in some way (so I don't go through batteries too fast).

In case you're wondering, I cannot use AC outlets (part of the projects rules). Plus, it wouldn't be safe for what I want to do with it...

[bobthecockroach]

Can you build a generator?

[guitarman531]

Originally Posted by bobthecockroach

Can you build a generator?

Ummm...prolly not...

Seriously though....is this even possible? We're building a Rube Goldberg machine and the end result is for the light to go on and we can't use AC wall outlets. I may be able to get a hold of a DC generator from the electronics lab....

[JerryLove]

Capicters don't make sense unless you want to strobe the light. Lights require a steady flow of power, and capacters generally serve one of two functions:

Buffering surges/reductions to make a steady output.
Buffering trickles to output rapidly. (a good way to use a small battery to power a big lightbulb for a short time)

In this case, a battery would already have a steady output. The bigger issue would seem to be AC/DC. Are you going to be able to use a DC light? I'm not sure what supplying a DC current to an AC bulb does one way or another.

How long do you need it on for? Do you need it outputting at full 40W? I suspect a lantern battery would be a decent choice if you can use a non-standard bulb or don't mind it being dim. Otherwise, a series of them or (as you suggested) you are left with using capaciters and hoping it doesn't need to stay on.

[Nate]

Two words:

Car. Battery.

Two more words:

Don't. Die.

[mtlcuz]

Why is this blog called lightbulbs?

[katmetal]

Can you build a generator?

HaHaHa!

Is this a 40 watt ac bulb? An ac bulb is designed to work with household current, 110 ac. You're gonna need a long string of "D" batteries hooked together. What are the parameters of your project? Did they give you guidelines to follow? For example, do you just need it to emit light, "dim" or brightly?

Unless you series alot of D cells, it would be difficult. You could however, series a few 6 volt lantern style batteries, that would give dim light for awhile, I believe. 6 lantern batteries, some wire & a switch would do it. Nothing to complicated...

[nate95366]

Originally Posted by guitarman531

I would prefer to use capacitors in some way (so I don't go through batteries too fast).

Capacitors don't generate their own energy, so they won't help your batteries last any longer. Everything else about capacitors I can think of was said above by JerryLove.

Nate

[guitarman531]

Thanks for the replies, everyone! I actually ended up utilizing a normal AC wall socket cord to power my light bulb (last May for a engineering projects class).

Thanks again!

[SccHarpGirl]

I thought this was going to be a thread like:

"How many engineering students does it take to change a lightbulb?"