adjusting lcd backlight brightness

Testing/Troubleshooting
1

With the LCD I’m using, the backlight current is too high if I turn the luminance pot to the max position. I tried adding the 10 ohm serial resistor that is required for using 5V to power the backlight, but now I can only adjust the brightness between maximum and just a little darker than max…

Is there a way to get the luminance pot to work from complete darkness to max brightness?

Regards, Dr Nick.

2

Hi Nick,

you could replace the 1k resistor (R4) before the lumincance pot by another one. This resistor limits the current through the backlight.

Best Regards, Thorsten.