spike021
Posts: 2
Joined: Sun Mar 06, 2016 3:20 am

Power supply specs

Sun Mar 06, 2016 3:24 am

I'm sure this gets posted a lot but I couldn't find anything for the specs I have, so please bear with me. Thanks!

I have a USB wall plug for a smart device (I don't remember if it was a tablet or what exactly). The specs on the plug say the Output is DC 5V 2.1A.

Would this be sufficient for a Raspberry Pi 3b?

In general I've read that a DC 5V 2.0A output works fine for most applications unless the Pi 3 will be used for heavier duty tasks. But then again, I'm just now getting into small electrical engineering now with the new Pi coming, so I just want to make sure.

Thanks in advance!

Rnd(100)
Posts: 9
Joined: Mon Feb 08, 2016 9:19 pm

Re: Power supply specs

Sun Mar 06, 2016 9:49 am

Basically, Yes and No,

If you were to plug in 4 USB peripherals each requiring 500mA, then you'd need a better power supply, it really depends on what you're going to connect to the RPi in terms of peripherals and how hard making the processor work.

Sure, you could run it off a 1A, 1.5A or 2A PSU, just depends on what you are powering from it !

spike021
Posts: 2
Joined: Sun Mar 06, 2016 3:20 am

Re: Power supply specs

Sun Mar 06, 2016 11:16 am

Rnd(100) wrote:Basically, Yes and No,

If you were to plug in 4 USB peripherals each requiring 500mA, then you'd need a better power supply, it really depends on what you're going to connect to the RPi in terms of peripherals and how hard making the processor work.

Sure, you could run it off a 1A, 1.5A or 2A PSU, just depends on what you are powering from it !
I think that makes sense, thanks!

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GTR2Fan
Posts: 1601
Joined: Sun Feb 23, 2014 9:20 pm
Location: South East UK

Re: Power supply specs

Sun Mar 06, 2016 12:13 pm

Rnd(100) wrote:If you were to plug in 4 USB peripherals each requiring 500mA, then you'd need a better power supply...
As the Pi3B is current-limited to a maximum of 1.2A across all 4 USB ports, this could never happen. There's a 2A rated polyfuse at the supply input, so the continuous current for the Pi3B plus all USB peripherals can never exceed 2A for extended periods. The additional 0.5A included in the recommended 2.5A Pi3B supply rating takes into account start-up surge as well as giving the PSU a little 'breathing space' during normal operation.
Pi2B Mini-PC/Media Centre: ARM=1GHz (+3), Core=500MHz, v3d=500MHz, h264=333MHz, RAM=DDR2-1200 (+6/+4/+4+schmoo). Sandisk Ultra HC-I 32GB microSD card on '50=100' OCed slot (42MB/s read) running Raspbian/KODI16, Seagate 3.5" 1.5TB HDD mass storage.

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