I'm thinking about making my own "arduino" low power board but I have a question about the atmega328. Is the output voltage on the pins always 5v or it depends on the input voltage I gave to the atmega?

Thanks in advance.

  • What Majenko said. | Note that 'rolling your own' for experience and/or fun is fine BUT you can buy good quality Chinese made clones for less than the cost of the components. Aug 25, 2015 at 15:55
  • @RussellMcMahon Yes, but the original and clones draw too much energy, I need something more simple that can save energy for a battery powered project. Thanks for the note anyways (:
    – LGhost
    Aug 26, 2015 at 1:09
  • The clones draw > minimum power only due to extra components on them Versions with no USB/serial IC are available (and even cheper) = Pro Mini. And regulator can be removed if safe Vcc can be provided. And onboard LED drive is optional. If desired all you have left is ~= uC IC and cryctal osc and current can be in the few microamps when doing nothing and not vastly more when crawling along with all or most peripherals off. There is a very good 'how to reduce '328 current draw article somewhere. Probably cited in this group and I can probably did it up. Aug 27, 2015 at 15:18
  • Well, an atmega328p can run on its own internal oscillator to save even more power.. And you can integrate it directly on the board rather than using connectors, so it's more "professional"/smaller. It depends on the needs
    – frarugi87
    Nov 26, 2015 at 12:52

1 Answer 1


It depends on the input voltage you give it. If you run the ATMega328p at 3.3V then you get 3.3V out. If you run it at 5V you get 5V out.

A word of caution about running at lower voltages: The chip can't run as fast when it has a lower supply voltage - that's why you will see the 3.3V Arduino boards running at 8MHz (or 12MHz at a pinch).

  • Thanks very very very much. That's exactly what I needed to know (:
    – LGhost
    Aug 25, 2015 at 13:56

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