What is the reverse voltage or the backward voltage in the LED that the voltage supply needed to overcome in order to allow LED to be in ON state? For example the
![1.: Comparison of forward voltage U LED of the IR LED measured by LED... | Download Scientific Diagram 1.: Comparison of forward voltage U LED of the IR LED measured by LED... | Download Scientific Diagram](https://www.researchgate.net/publication/334491523/figure/fig23/AS:781291549110276@1563285829450/Comparison-of-forward-voltage-U-LED-of-the-IR-LED-measured-by-LED-driver-IC-and.png)
1.: Comparison of forward voltage U LED of the IR LED measured by LED... | Download Scientific Diagram
![batteries - 9V powering to the safest maximum brightness of 4 IR LEDs in series - Electrical Engineering Stack Exchange batteries - 9V powering to the safest maximum brightness of 4 IR LEDs in series - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/GFGGz.png)