UNO connect method 3.3v and 5 v together

I am looking for a connecting method to join 5 and 3.3 V together comes out 8.3 V. The connection draft was attached and may i get yours advise.on it.
Thank you so much.

Frank :slight_smile:

You can't. They share the same ground. You'd have to have some way to put them in series and that's just not possible.

You could use one of these. Not much more than $1 each.

so, it is impossible to connect+ 3.3v to +5.5 v , am i right? but what is the reason unable to connect....

so, the only way is to additional supply by an ac to dc transformer.


Hi Paul,
This is my attached image before
, and what is the comment on it?
Frank :slight_smile:

He was probably just posting it so people could see it directly without having to download your file.

The reason you can’t connect them that way is you are creating a short circuit between a higher potential and a lower potential. So you end up with 1.7V across almost 0 resistance. If you look at Ohm’s Law, I = V/R so very low R means very high current which means very much heat and most likely smoke.

Hi Frank.

I wanted to see the image, and because I am viewing the forum on my phone the easiest way is to attach it to a post. It would have been helpful if you had done this. How to do that is not well explained in the forum guide, but you first attach the picture as an attachment as you did, then post, then copy the image location, edit the post and insert the image.

Once I had done so, I found I could not read your handwriting. Did you try to hand write words on the screen with your mouse? If you don't have a schematic editor installed that you are familiar with, it's quite acceptable to draw your schematic on paper and scan/photo that.

so, it is impossible to connect+ 3.3v to +5.5 v , am i right? but what is the reason unable to connect.

It is the same reason that you can not jump over a wall in two jumps. You have nothing to push against for the second jump. In this case electricity works the same. Both voltages are relitave to the ground, so they both push against the same point.

What do you need 8.3Vdc for?

Tom.... :slight_smile: