AboutDave Nyce Expertise I have been an electronics engineer for 25 years. I can answer questions on analog and digital circuits and my specialty is sensors.
Experience I am the inventor on 23 US patents, and also some foreign ones. Developed sensors for over 25 years. Licensed private pilot (airplane and rotorcraft), have HAM radio license. I'm not an expert in computer networking.
Question I am having a lot of trouble in this type of problem and any help will be appreciated. The dark resistance of a photoconductive cell is taken to be the resistance of the cell at 1 Lm/m^2 . In order to establish this specific illuminance we should stand away from a 100 watt light bulb (1700 lumens). What would be the distance in meters?
Answer Assume your 1700 lumen bulb is contained at the center of a spherical surface, and all of the light falls on the inside wall of that surface. Find the radius of a sphere that has an area of 1700 meters. Then the light intensity on that area is 1 lumen/m^2. That radius is your distance.
