What is the difference between lux and lumens?

 It is good to know the difference between Lux and Lumens if you are designing lighting products.

The core difference can be summarized as follows:

- Lux is a measure of illuminance, the total amount of light that falls on a surface

- Lumens is a measure of luminous flux, the total amount of light emitted in all directions.

Information Reference: 

Voltage controlled Current Source Circuit

 

This circuit control the output current flow effectively. Reference voltage V1 can be set to desire output current, for instance V1=700 mV is setting output current to 670 mA.