Hi,
I'm trying to power my 40 watt lightbulb, and I've been at this for a bit, and was told this morning I would need 22,000 "C" batteries, which seems like it would make my lightbulb explode...
Anyway, my standard C battery I am using has 1.5 volts and 7.5 amps when I tested it. Now, my first possible pitful of not being sure is, if I stack these batteries together, I know the volts will just add, but will the amperage stay constant?
Now, assuming the amps did stay relatively constant, I figure it would take 5.3 volts to power my 40 watt lightbulb. This is using the following equation:
P = iv
40 = 7.5x
x = ~5.3
Now, assuming 1.5 volts per battery, i figure that 4 C batteries should more than do the job.
So, with my 4 C batteries hooked up, I test again the current and voltage. I am now getting 6.1 volts (About what I expected to see) and also 9.5 amps. This is about 58.0 watts, which I figure should power my 40 watt lightbulb.
But, now that I have my lightbulb hooked in, it doesn't even glow. And, when I re-measure everything, I find that I get 104 mA and 5.9 Volts, which of course is only 0.6 Watts, not nearly enough to power my lightbulb.
My question is, how can this be? Is it the extra ohms of resistance in my lightbulb? Does my lightbulb really pull only 40 watts of power? If so, how come it takes that much...
Thank you,
Richard Bewley