Using 12V 1000mA wart instead of USB from laptop to power. Need reassuring

As you can tell I'm a bit new to this.

As the title states, I've plugged my arduino into a 12V 1000mA AC to DC adapter. I read that this is supposed to be fine, due to the arduino having a voltage regulator built in. However, I notice that my LCD display glows yellow and has way too much contrast. Can I just get reassurance that this is okay? And that changing the resistance value on the variable resistor for the display contrast will do the trick.

p.s, I also have other various components such as a HC-05 and accelerometer etc. Can I just confirm that these will all be okay?

Thanks in advance!

At 12V that regulator can't handle much more than the Arduino itself before overheating.

Use a regulated 5V power supply instead. Or if you need 12V in your project, add a 12V-5V buck converter for your 5V needs.

Cool, thanks for the heads up! Just wanted to be sure I wasn't going to potentially damage things

I hope you do realise you can’t reliably power that LED display off the Arduino’s 5V pin when powering the Arduino with a 12v supply…

rosstoal:
Cool, thanks for the heads up! Just wanted to be sure I wasn't going to potentially damage things

And indeed you could.

A 12V 1000mA AC to DC adapter - if it is the old transformer-rectifier-capacitor type and not a switchmode regulated supply, will tend to give over 17 V unloaded, possibly even 20 V, which may exceed the rating ot the on-board regulator.

I cannot see why your LCD display would glow yellow unless it is in fact, a yellow display. Does it not have a contrast control potentiometer on it?

You should consider the on-board regulator useless for anything other than testing of the Arduino board with no other components connected. It is really a "legacy" part of the design. Some variants of the UNO such as the "RoboRed" however have a proper (switchmode) regulator included.

Hi,
Do you have a DMM to measure your circuit voltages?

Tom... :slight_smile: