1602A LCD without poti?


i want to test my 1602A LCD display and have no Poti.
How can i do that?

You do need a potentiometer to adjust the contrast.

Have you found an example of how to wire it? LiquidCrystal library... HelloWorld

Your display will be blank if you do not connect pin 3 or if you connect it to VCC.

If you do not have a potentiometer you can try connecting pin 3 to GND. This will produce an acceptable although not optimum result on many displays.

You can create a voltage divider (which is how the potentiometer works) with two resistors. Start with 10K between VCC and pin 3 and 1K between pin 3 and GND.

You can just use a single resistor, probably around 1K or less, between pin 3 and GND.


You only ever need a single resistor between VO (pin 3) and ground. (Because there already is a 11k resistor ladder to VCC on the LCD board.) The use of a potentiometer is a misunderstanding derived from an original application note.

Start with a 470 ohm resistor. Try a 1k or connecting pin 3 straight to ground to see if either is an improvement and you could then try values in between. Once set, the value will not need to be altered (as long as your power supply is stable).