Luminosity regulating circuit for white LEDs, has regulator supplying direct voltage to LEDs having high operating voltage and including potentiometer and threshold resistor mounted in series, where LEDs are arranged in series of four

摘要

The circuit has an LM317T adjustable voltage regulator (11) supplying a direct voltage to LEDs (2) i.e. white LEDs, having an operating voltage higher than 3 volts, where the LEDs are arranged in series of 4. The regulator has a potentiometer (12) and a threshold resistor (13) that are mounted in series, on a gate. The potentiometer has a shunt resistor (14) placed parallel to optimize an effective range of voltage regulation of the LEDs on its entire regulation course. The LEDs are formed of an indirect gap semiconductor substrate and made of gallium nitride or gallium indium nitride.