From what I've seen of articles and videos online, everyone seems to be using the 3.3V GPIO pin. I have an LCD screen which requires a 5V power supply and I wondered whether it would be safe to use the Raspberry Pi's 5V GPIO pin? If you can't use it, what is it there for?

I have a 16x2 KS0066 (apparently compatible with HD44780) LCD screen Picture of LCD screen

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    As long as the LCD does not need more than 200ma (assuming you are using 1A supply on model B) then you are fine to use it as supply. Model B can peak at 800ma so 200ma is safe to use as spare from the 5V Pin. If you need more use another power supply/board to connect direct to the power supply if it is more than 1A – Piotr Kula Aug 20 '12 at 15:21
  • I bought this before I knew what I was doing: oomlout.co.uk/lcd-display-16-x-2-p-212.html The technical specifications seem to indicate it will draw 1.2mA@5V. – Mark Ingram Aug 21 '12 at 7:32
  • I think the 5V pin gives you less than 5V because it is subject to use by other resources, however the 3V3 is consistently 3V3. I am not with my Pi until weekend but use a multimeter (if you have one) and you will see you don't get the full 5V. – AnthonyBlake Aug 21 '12 at 9:06
  • @AnthonyBlake because the 5V is not regulated on pcb but supplied by external power. 3v3 is regulated from the 5V rail. A slight voltage drop will not affect this LCD screen. – Piotr Kula Aug 21 '12 at 9:57
  • @ppumkin ah okay, I am quite new to electronics so I didnt know if that would have an effect. – AnthonyBlake Aug 21 '12 at 10:09

There is a brilliant tutorial at Adafruit how to connect a 16x2 LCD to the Raspberry Pi using the 6 I/O pins.

enter image description here

As this is just a small LCD screen and you said in your comments it only uses 1.2mA you will be perfectly fine to use the +5V GPIO Pin to power the LCD .

When you want to use more peripherals though you would have to look into using an I2C interface instead.

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    the link works perfectly fine for raspberry pi model b 2 if all the pins are correctly configured. Thanks @ppumkin – ravi.zombie Jan 18 '16 at 8:47

Go for it! You should, of course, look at the schematic and note their is a 1A fuse on the supply; depending on your USB peripherals you will be limited to between 200 - 500mA. If this is not enough, you could power the Raspberry Pi via the 5V pin.


It should be fine. The backlight is the main power user, and it's typically only 20mA in addition to the 1mA that the LCD part uses.

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