Intigrating a 20x4 LCD display into a project, hoping someone could take a look at the attached schematic and make sure I'm not doing something stupid with the transistor for the backlight drive....
**broken link removed**
Cant get a definitive answer from the datasheet, but I believe that a current limiting resistor is not needed (provided on the LCD), correct?
datasheet lists LCD max current at 60mA.
Hfe of transistor is 100
You may find when it arrives that it includes a resistor, datasheets are often old and if they have specs for the backlight LED it may be an old spec or the spec might just be for the LED, and ignores the fact that someone has since added a resistor on the PCB in one of the more recent production batches.
You may find when it arrives that it includes a resistor, datasheets are often old and if they have specs for the backlight LED it may be an old spec or the spec might just be for the LED, and ignores the fact that someone has since added a resistor on the PCB in one of the more recent production batches.
Interesting! Thanks for the info. I've got LCD samples here from quite a few manufacturers and it's been a long time since I have seen one with no resistor.