Powering an Arduino: A question I may look very silly for asking!

Question: Can the 3.3V port used to provide input power to the ESP also output voltage to an LED?

When the ESP is in deep sleep mode, does it stop drawing current and start outputting the power reserves it should be using to stay in deep sleep mode to the status LED?

Backgroud: As I mentioned in another post, I'm currently investigating the deep sleep functionality on an ESP32 board using touchpad wakeup. It works exactly as deep sleep should, and can be woken, for about 30 seconds, and then it completely powers down and after this point it cannot be woken unless the battery is completely disconnected and reconnected.

My current thought is that it stops drawing power from the battery when it enters sleep mode (else it would run until the battery died.) and that it relies on some residual power while it's in sleep mode. Now that I'm typing that out, I'm not sure that's even a remotely correct assumption...

Anyway, the board is powered through a 3.3 V voltage regulator, and it, of course, is connected to several capacitors for protection. There is one status LED also connected to the voltage regulator's output.

When the board enters deep sleep this LED stays on until the board completely powers down. Initially, I believed this was simply because the capacitors had some charge left, or because there was still some current coming from the battery, but now I'm wondering something else, and I may be very stupid to ask this (this is the question from the top):

Can the 3.3V port used to provide input power to the ESP also output voltage to an LED? When the ESP is in deep sleep mode, is it outputting the power reserves it should be using to stay in deep sleep mode to the status LED?

barrel connector > V In > 5 v regulator > 5 v pin
_____________________________ > 3.3 V regulator > 3.3 v pin

no

Sorry, I'm not following you Emeritus,

I'm only inputting 3.3V to the Arduino, what do you mean by barrel connector?

I drew this up to maybe make things more clear:

Start by telling us what "Arduino" or apparently, ESP device (not being an actual Arduino) you are talking about!

Then perhaps tell us what you wish to do.

Since this is apparently a cross post, perhaps "report" your own post as such to a moderator and request it be put back on to the original post where it was supposed to be, so people know what you are on about?


Capture.PNG

Clefsphere:
Question: Can the 3.3V port used to provide input power to the ESP also output voltage to an LED?

Can the 3.3V port used to provide input power to the ESP also output voltage to an LED? When the ESP is in deep sleep mode, is it outputting the power reserves it should be using to stay in deep sleep mode to the status LED?

You don't say which Arduino you are using, but most have only a little power available at the 3.3v pin and having a LED thereon is probably not such a great idea.

I'm using an ESP32 WROOM

Datasheet: https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32_datasheet_en.pdf

As you can see on the datasheet, page 3 has full pinout, I am using pin 2 to power the device, and this is the 3.3V pin I'm talking about.

My last post was on the same subject, but asked in a very general way. This one pertains specifically to power and the LED, while the last one was just a general "Why is my controller exiting deep sleep?"

There is some information there. Here is the link:

https://forum.arduino.cc/index.php?topic=621415.msg4210228#msg4210228