Wawa:
Look at the diagram on page 8 of the datasheet.
You see a voltage divider (string of 1k resistors) inside the chip.
One end of the string is connected to a reference voltage, and the other end (normally) to ground.R2 in your diagram increases the value of the bottom resistor to 18k+1k= 19k.
That "lifts" the reference voltage on the lowest opamp (first LED) to 19/(19+9) * Vref, or ~68%.Note that the chip will overheat/shutdown of you power it from 12volt and drive more than a few LEDs.
12volt LED power is ok in dot mode, but not in bar mode.
Leo..
In the string of comparators, are the comparators the same value or how does it not activate them all at once.
For my r2 resistor, where does the extra 1k come from?
Also im still not 100% positive what the reference voltage does?
Thanks for response!!!