Quote:
quote:Originally posted by mere
Can anyone tell me approx how long the leds will last when hooked up to a 9 volt battery?
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If you knew the current supply/draw specs of both the battery (in mAh) and the LED+resistor (in mA) you could calculate it. For example, a 250mAh supply would power a 40mA draw for 6.25 hours. (in a perfect world)
Alkaline batteries are best for low-current extendeded usage. Lithium batteries are just the opposite, best for limited use high current, like a photo flash.
Also, you'd likely get considerably longer life by using multiple AA cells instead of a single 9V cell.