I want to install some external LEDs to my mister using the P4 header, but I can't find any guides for doing so.
This post has the LEDs with resistors in front of them: viewtopic.php?t=1186. Are these actually necessary or are resistors labelled RN16 on this diagram enough? https://github.com/MiSTer-devel/Hardwar ... rd_6.1.pdf
Thanks!
Are resistors necessary when connecting external LEDs?
-
advert2021
- Posts: 3
- Joined: Sun May 09, 2021 9:26 pm
- Been thanked: 4 times
-
kathleen
- Top Contributor
- Posts: 421
- Joined: Fri Jun 26, 2020 4:23 am
- Location: Belgium
- Has thanked: 243 times
- Been thanked: 138 times
Re: Are resistors necessary when connecting external LEDs?
Hi advert2021,
The resistance is mandatory to limit the current to the led (this I(f) is depending of the LED that you want to use), same for the voltage drop of the led, it can be 1.5, 2, 3 volts..... As long as you know the characteristics of your LED it is easy to select the proper resistance
Here is a link to easily calculate the resistance for a given source (Uin) and a given led : https://ohmslawcalculator.com/led-resistor-calculator
PS : it is obvious that the current needed by the LED(s, in case for any reason you want to make a X-Mas tinsel) cannot be higher than what the source can provide.
The resistance is mandatory to limit the current to the led (this I(f) is depending of the LED that you want to use), same for the voltage drop of the led, it can be 1.5, 2, 3 volts..... As long as you know the characteristics of your LED it is easy to select the proper resistance
Here is a link to easily calculate the resistance for a given source (Uin) and a given led : https://ohmslawcalculator.com/led-resistor-calculator
PS : it is obvious that the current needed by the LED(s, in case for any reason you want to make a X-Mas tinsel) cannot be higher than what the source can provide.
かすりん