On Sep 17, 1:11*pm, Jon Anderson wrote:
Bought an LED ring light for my B&L microscope, a great investment!http://cgi.ebay.com/ws/eBayISAPI.dll...m=400017698337


The power supply is a 12v 500mA.

The power supply is a switching supply, since it automatically changes
from 120 to 240 VAC input. I'm sure that all the LED drive circuitry
is in the ring light itself based on the variable illumination
feature. http://store.amscope.com/led-64s-yk.html

If the unit actually draws anything near 500 mA, a set of alkaline AA
cells (which are rated at 1700 mAh or more) should power it for more
than a half-hour to as much as an hour under practical conditions.

Northe