PowerWise® Design University
POWER 105 - Lighting
Why is current regulation preferred over voltage regulation in driving white LEDs?
The LED forward knee voltage variation across manufacturing batches is large
The voltage regulation tolerance required can not be achieved
The LED current voltage relationship is exponential
The light output of an LED is a direct function of the current and an indirect function of the voltage
What is the function of light output to temperature?
Linear increase
Exponential increase
Exponential decrease
Linear decrease
Which of the following is most mono-chromatic (single wavelength)?
White LED
Tungsten lamp
Laser
Noon Sun light
What is the advantage of EL back lighting over LEDs?
EL is bright and can pure white
EL is thin and can be cut into any shape
EL works best in high humidity
EL can outlast an LED
Which of the following is NOT a visible wavelength?
470nm
530nm
650nm
770nm
What is the difference between radiant power and luminous flux?
Luminous flux accounts for the human eye sensitivity over the light spectrum
There is no difference
Radiant power is the transmitted energy and Luminous flux the received intensity
Radiant power is omni directional, Luminous flux is directional
