Re: ATM A little electronic help on my Foucault tester]

[Paul Cousoulis <paulcsouls@worldnet.att.net>]

Hi James

According to the Gilway Technical Lamp Engineering Catalog:

"The output of LEDs is typically expressed in millicandela(mcd). The
candela is defined as the number of lumens per steradian of solid angle.
It is usually measured along the projection axis of the device and gives
the eye's response to the light."

To choose a resistor for your LED.

Resistance = (Battery_Voltage -
LED_Forward_Voltage)/(LED_Normal_Current) 

Clear Skies
Paul