/diy/ - Do It Yourself » Thread #895062

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Anonymous Thu 29 Oct 2015 12:19:20 No.895062 View Reply Report Delete

I wanted to make a battery-powered lamp. Seemed so simple, right?

Then after buying some lamp wire, some D cell batteries and a bulb, I noticed that my bulb uses 120v and a D cell only outputs 1.5v

Did I dun goofed? Is it even feasible to power a 40-60w light bulb with a (relatively) small power supply?

pic unrelated

Anonymous

Anonymous Thu 29 Oct 2015 12:23:08 No.895065 Report Delete

Quoted By:

>>895062
yeah, but you need leds

Anonymous

Anonymous Thu 29 Oct 2015 13:43:27 No.895094 Report Delete

Quoted By: >>895114 >>895460

>>895062
Think about your power equations.

P=VI .

V is 1.5v, so for 60w, you'll need 40A.

This is a fuckload of amps. Most of your house wiring is not rated to 40A.

Time to get a bit more realistic, and look at how the lamps you can buy do it. Your common or garden maglite has six or eight D-cells, and runs to about 3-4 watts.

So you're looking at using a 0.5w bulb or LED module. Not a 60w house bulb.

Anonymous

Anonymous Thu 29 Oct 2015 14:03:22 No.895114 Report Delete

Quoted By: >>895125 >>895128 >>895219 >>895256

>>895094
Not OP but are you autistic? Most houses have light fixtures that power 40, 60, and 80W light bulbs off of 120v. Ohm's law is irrelevant because he won't even get the bulb to emit light at 1.5v, even at infinite amperage. Also do notice that the bulb calls for 120 VAC, not DC, which will make a difference.

>>895062
OP. 1) You are able to wire D cells in series (connecting one end of the cell to the end of another cell to combine voltages) which will allow you to get x*1.5volts, however you will still need to buy a bulb or LED light (which is preferable) that is rated for DC use.

etc

etc Thu 29 Oct 2015 14:28:54 No.895125 Report Delete

Quoted By: >>895128

>>895114
If it is a filament bulb then you can definitely run it off of DC, but not 1.5 volt DC. Just putting it out there.

etc

etc Thu 29 Oct 2015 14:33:55 No.895128 Report Delete

Quoted By:

>>895125
>>895114
To expand on this, you would need to provide the bulb with the exact amount of power with DC that it is rated for with AC.

In other words; a bulb rated for 220 volts AC (RMS) will be just as bright when connected to 220 volts DC

Anonymous

Anonymous Thu 29 Oct 2015 15:30:02 No.895153 Report Delete

Quoted By:

https://youtu.be/DcFHZMhnV2g?t=168

Anonymous

Anonymous Thu 29 Oct 2015 18:04:53 No.895219 Report Delete

Quoted By:

>>895114
Not the guy you were replying too but how was anything he said retarded? A 60w bulb running on 120v is going to draw like half an amp.

Anonymous

Anonymous Thu 29 Oct 2015 18:33:59 No.895256 Report Delete

Quoted By:

>>895114
>>>this is why your idea won't work
>hey, retard, that idea doesn't work
>gets junior-high physics problem wrong
>your a tard

Anonymous

View Same Google ImgOps iqdb SauceNAO 6UkENKw.jpg, 74KiB, 508x720

Anonymous Thu 29 Oct 2015 23:52:28 No.895434 Report Delete

Quoted By:

god bless the masturbator!

Anonymous

Anonymous Fri 30 Oct 2015 01:21:22 No.895460 Report Delete

Quoted By: >>895480

>>895094
Worst application of ohms law I've seen

Anonymous

Anonymous Fri 30 Oct 2015 03:22:55 No.895480 Report Delete

Quoted By:

>>895460
The great thing about an anonymous board is that you can be wrong about several things (what voltage mains is, how tungsten bulbs work, etc.), then get telt, but because you're anonymous you can just draw a line under it and move on.

You're not forever marked as the guy who thought you needed special incandescent bulbs for DC.

You got corrected today. You learned something. No need to get salty.

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