Hi,
I have a Nano board in which I need to short the pins of reverse voltage blocking diode installed between the USB connector’s bus voltage and the board’s 5V bus, for a DIY project. On this Nano board (attached picture), can someone please point which is that diode/pins?
Thanks
Paddy
That big black blob on the top left is probably the diode. Your photo is to dark to be sure.Hopefully you have some more parts available as a mistook can fry the Arduino and possibly your computer.
Why do you think it even has one?
An official Arduino Nano doesn't.
Thanks gilshultz. I have the same guess.
Thanks jim-p - I think there is one, because I connected my servo as I was instructed here in this link-below without shorting the diode, and smoke came out of it as the doc below said :-)... This is the second nano, I want to make sure I get it right. Also the doc below shows a different Nano board, where the diode is in different place. So I could not correlate; hence put the question here..
https://docs.google.com/document/d/1VV9CunwyOTu5k_3kxSH5o6iANpJEpwg5Pu7IEfHsnA0/edit?tab=t.0
I'm just curious, but why do you need this potentially dangerous thing?
And anyway, why don't you search the Nano's schematic online and identify the diode yourself?
Look again.
D1 bottom/ middle.
Those blocking diodes frequently fry when you draw too much current from the Nano pins.
Any 1A Schottky diode can be used to replace them.
It seems to be the small black part near the left pin of the regulator in post#1.
Leo..
Op wanna bridge the diode.
Bad idea.
It's function is to protect (backflow into) the USB port of the laptop/PC.
Soldering/removing an smd diode is not as hard as you might think.
Leo..
Yeah. Especially when you read this:
Sounds like the magic smoke will escape soon...
That is not an "official" classic Nano schematic and it contains an number of strange design features, for example no caps on the voltage regulator and D4 at least looks like it will get a hammering.
That is not a reverse voltage blocking diode.
If you apply reverse voltage to 5V or Vin how could that diode prevent a reverse voltage??
Of course not, it's actually for "clones" (see that "ch340"?). And I posted it because it looks like the OP author has that, not an "official" one.
Anyway, I can't still get what's the OP goal...
The OP has the mis-understand that there is a reverve voltage blocking diode on his board when there isn't any. Everyone here seem to think that the diode between USB and +5 can some how prevent a reverse voltage on 5V or Vin when it could only prevent a reverse voltage on the USB connector and how could that happen
I can only imagine that the OP's requirement is for 5v derived from the USB connector and not 5v minus the ~0.3v drop across a Schottky diode. That, irrespective of the discussion about the intended role of that Schottky diode.
This is, incidentally, one of the areas where a Uno design is superior to that of the Nano.
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