11 May
2010
11 May
'10
11:05 a.m.
On 11 May 2010 at 11:14, John Foust wrote:
The four bulbs were identical as far as I could tell.
Same
flashlights, off the rack, as I said "I bought four $1 flashlights".
Quite possibly Far East-origin flashlights? Put together from
whatever the local spot market makes available. BTW, the local
Harbor Freight "Chinese Tool Store" is giving away 9 LED flashlights
with spun aluminum housings (3 AAA batteries included), so these
bargain things can't come to much on the wholesale market.
I was perplexed. I assume it was due to some initial
high resistance
that dropped once one of the bulbs won the battle to light, which
lowered the resistance for that bulb.
More likely, mismatched bulbs. Incandescent Christmas-tree strings
are typically series-connected with good results.
I was moreso perplexed about the poor specification
for this take-home
assignment. How the average student was supposed to come up with four
bulbs and a power source to correctly light them, when instructed to
use "Christmas bulbs"? LEDs? Incandescents? What voltage?
In fact, most Christmas-tree (wire-lead) replacement lamps will
operate on 6V just fine. I've got a string that I decorate my tuba
with at Christmastime that runs from 4 C cells at pretty much full
brightness.
Even a 120V incandescent will typically show some glow at 12V, so
voltage (as long as it's not too high) with incandescent lamps has a
fairly wide range.
--Chuck