0
\$\begingroup\$

I have a situation where I need to power an Arduino Uno R3 from a ~16V power supply.

The problem is I have no idea of the implications of voltage dropping. I think I just need a 100 Ohm resistor.

So, in case I am right, my actual question turns into: When is it better to complicate a circuit with a Zener diode?

I will also attach a photo since I understand it is easier to read from it.

enter image description here

Edit 1: A neighbor suggested a 4V LED that would also indicate it's working.

\$\endgroup\$
3
  • 3
    \$\begingroup\$ Don't use a voltage divider (resistors) or a zener. Use a DC/DC converter \$\endgroup\$
    – Huisman
    Commented Jul 26, 2019 at 6:57
  • \$\begingroup\$ Read This SE EE question and then this answer and you should have a VERY good idea of what to do. The other answers are also useful - the above one is mine :-). \$\endgroup\$
    – Russell McMahon ♦
    Commented Jul 26, 2019 at 13:23
  • \$\begingroup\$ Reducing the Vin to theUNO to closer to the processor operating voltage will reduce the heat in the onboard regulator. \$\endgroup\$
    – Russell McMahon ♦
    Commented Jul 26, 2019 at 13:24

1 Answer 1

Reset to default
1
\$\begingroup\$

If you need to power it, it is not a good idea. What happens, if your Arduino suddenly draws more current? -> The voltage drop across your resistor increases, the voltage on your Arduino supply decreases. Same case with diode.

Use a simple linear regulator or a switching DC/DC converter module.

\$\endgroup\$
2
  • \$\begingroup\$ ... and we usually use the battery negative as the common or GND (and not the positive). \$\endgroup\$
    – Transistor
    Commented Jul 26, 2019 at 6:56
  • \$\begingroup\$ this is why it's best to ask, thank you \$\endgroup\$
    – Joita Dan
    Commented Jul 26, 2019 at 7:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.