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[on:]

Hi,
I'm running an UNO with an Arduino Ethernet shield and a sparkfun color LCD shield.

When I use a 12V, 2A, center positive  power source it resets itself every once in a while and gets very hot.

When I use a 9V, 300mA, 2.7VA , center positive power source it doesn't power the screen properly.

I am wondering if using a USB power adapter will make any difference.

What power supply would you recommend?

Thank you.

[Reply #1 on:]

https://www.sparkfun.com/products/9363

Here is the LCD

[Reply #2 on:]

one of these USB plugs and a normal usb cable got it working, I'm just wondering what power adapter I should use.. In case I ever need to use the USB for something else.

[Reply #3 on:]

one of these USB plugs and a normal usb cable got it working, I'm just wondering what power adapter I should use.. In case I ever need to use the USB for something else.

Presumably something that can supply less than 12V and more than 300mA.

[Reply #4 on:]

Maplin
L67BQ 9V 600mA £11.99
L46BL 9V 2.25A £19.99

[Reply #5 on:]

When I use a 12V, 2A, center positive  power source it resets itself every once in a while and gets very hot.

In that set-up, if you need more than 200ma, I would seriously question if something is wrong.

[Reply #6 on:]

When I use a 12V, 2A, center positive  power source it resets itself every once in a while and gets very hot.

In that set-up, if you need more than 200ma, I would seriously question if something is wrong.

Not sure what point you're trying to make.

Ethernet shields take 150mA or more, and the LCD probably needs 75mA or more, and Arduino 40mA, all adds up to more than 200mA - hence the excessive heat from 12V leading to thermal-shutdown of the on-board regulator.

Solution is either good USB PSU, or 7..9V supply to the barrel jack, or even a DC-DC converter (good choice for vehicle as supply is 12V anyway)

[Reply #7 on:]

PS: What does this have to do with the UK? I'm intrigued by the mental leaps needed to come up with the question.

[Reply #8 on:]

PS: What does this have to do with the UK? I'm intrigued by the mental leaps needed to come up with the question.

DC is different in the UK although the third post did show a standard UK mains plug (yes, they really are that big, rated 240V and 13A).

[Reply #9 on:]

Because a PSU has to match the mains voltage of the region its used in?  240V 50Hz in the UK.

[Reply #10 on:]

Because a PSU has to match the mains voltage of the region its used in?  240V 50Hz in the UK.

and France  and Germany and Italy and Switzerland and Sweden and

[Reply #11 on:]

How do you have the LCD backlight connected? I don't normally power LCD backlights from the +5v supply, I power then from the incoming +9V or +12V supply through a series resistor. That way, the current taken by the backlight doesn't heat up the regulator, and it's less likely to go into thermal shutdown.

[Reply #12 on:]

Because a PSU has to match the mains voltage of the region its used in?  240V 50Hz in the UK.

Nope. It's been 230V for quite a long time now (since 1983 I believe...) - to harmonize with Europe.