I have built a very primitive voltage booster with a push button.

[![enter image description here](https://i.stack.imgur.com/1tXvV.jpg)](https://i.stack.imgur.com/1tXvV.jpg)

Now I would like to add my ATMEGA328 to automate the switch. The problem I'm facing is that I want to measure the output voltage as well, but my ATMEGA's VREF is set to internal 1.1v.

I could make a simple voltage divider in parallel and take the reading from there, but I'm a bit confused about the following:

If my max output voltage is 20v, then my R1 value should be 190kΩ and R2 value should be 10kΩ, BUT what happens if my output voltage drops from 20v to 3v, wouldn't that cause R1 and R2 to try to 'draw out' more current from the capacitor? or is this the proper way of doing this? 

The boost converter voltage will change from 0v to 20v in random phases, so basically what I'm trying to do is find a proper way to do this in circuit:

```
voltage_reading = voltage_from_capacitor / 20v;

```