Anyone familiar with wiring GPIO on RPI?

I have seen a few examples of wiring a red LED directly from the RPI GPIO pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma, so if I use the 5V power on pin 1 would I end up with 5V - 3.3V = 1.7.
1.7 V = 20 mA ╫ R or rephrased: 1.7 V / 20 mA = R and when we solve that we get: 1.7 V / 20 mA = 1.7 V / 0.020 A = 85Ω ?

Thanks

---
■ Synchronet ■ The Empty Keg BBS emptykeg.synchro.net:82 Lake Echo NS Canada

Re: Raspberry Pi GPIO
By: Mortifis to All on Sun Dec 09 2018 01:38 pm

pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,

where do you get your 3.3 number? the chart i am looking at on the internets sez whites are in that range and greens are 2-2.3

i can check out leds at work and see what the specs are.
---
■ Synchronet ■ ::: BBSES.info - free BBS services :::

On 12-09-18 12:22, MRO wrote to Mortifis <=-

@VIA: VERT/BBSESINF
Re: Raspberry Pi GPIO
By: Mortifis to All on Sun Dec 09 2018 01:38 pm

pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,

where do you get your 3.3 number? the chart i am looking at on the internets sez whites are in that range and greens are 2-2.3

2-2.3 is more in line what what I remember as well. Certainly not 3.3. Yeah, white LEDs weren't around when I last studied this. :)


... You... In the red shirt... See what that noise is...
--- MultiMail/Win v0.51
■ Synchronet ■ Freeway BBS, Bendigo Australia. freeway.apana.org.au

Re: Raspberry Pi GPIO
By: Mortifis to All on Sun Dec 09 2018 01:38 pm

pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,

where do you get your 3.3 number? the chart i am looking at on the internets sez whites are in that range and greens are 2-2.3

i can check out leds at work and see what the specs are.

From here as well as other sources. Just curious which resistor I should use.

https://www.petervis.com/electronics/led/led-resistor-calculator.html

---
■ Synchronet ■ The Empty Keg BBS emptykeg.synchro.net:82 Lake Echo NS Canada

On 12-09-18 12:22, MRO wrote to Mortifis <=-

@VIA: VERT/BBSESINF
Re: Raspberry Pi GPIO
By: Mortifis to All on Sun Dec 09 2018 01:38 pm

pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,

where do you get your 3.3 number? the chart i am looking at on the internets sez whites are in that range and greens are 2-2.3

2-2.3 is more in line what what I remember as well. Certainly not 3.3.
Yeah, white LEDs weren't around when I last studied this. :)

From here as well as other sources. Just curious which resistor I should use.

https://www.petervis.com/electronics/led/led-resistor-calculator.html

---
■ Synchronet ■ The Empty Keg BBS emptykeg.synchro.net:82 Lake Echo NS Canada

On 12-10-18 10:38, Mortifis wrote to Vk3jed <=-

From here as well as other sources. Just curious which resistor I
should use.

https://www.petervis.com/electronics/led/led-resistor-calculator.html

I happen to still agree with MRO, I think that site is wrong, but only for the green LED, the other values look reasonably accurate.


... An aphrodisiac and a floor wax?
--- MultiMail/Win v0.51
■ Synchronet ■ Freeway BBS, Bendigo Australia. freeway.apana.org.au

Re: Re: Raspberry Pi GPIO
By: Mortifis to MRO on Mon Dec 10 2018 10:38 am

where do you get your 3.3 number? the chart i am looking at on the internets sez whites are in that range and greens are 2-2.3

i can check out leds at work and see what the specs are.

From here as well as other sources. Just curious which resistor I should use.

https://www.petervis.com/electronics/led/led-resistor-calculator.html

i'm looking at digikey. there's a standard led here and the green one is spec'd at 2.1-2.6

go on digikey and look up the datasheets
it's important to know what you are working with
---
■ Synchronet ■ ::: BBSES.info - free BBS services :::

Re: Re: Raspberry Pi GPIO
By: Vk3jed to Mortifis on Tue Dec 11 2018 07:00 am

On 12-10-18 10:38, Mortifis wrote to Vk3jed <=-

From here as well as other sources. Just curious which resistor I should use.

https://www.petervis.com/electronics/led/led-resistor-calculator.html

I happen to still agree with MRO, I think that site is wrong, but only for the green LED, the other values look reasonably accurate.

also COLOR is spelled wrong!

*BLACKGUYPOINTINGATTEMPLE.PNG*
---
■ Synchronet ■ ::: BBSES.info - free BBS services :::

Re: Re: Raspberry Pi GPIO
By: Vk3jed to Mortifis on Tue Dec 11 2018 07:00 am

On 12-10-18 10:38, Mortifis wrote to Vk3jed <=-

From here as well as other sources. Just curious

which resistor I

should use.

https://www.petervis.com/electronics/led/led-

resistor-calculator.htm

l

I happen to still agree with MRO, I think that site is

wrong, but only

for the green LED, the other values look reasonably

accurate.

also COLOR is spelled wrong!

I went to an electronics supply/service outlet, the values on
the site are accurate. COLOR vs COLOUR seems irrelevant lol

---
■ Synchronet ■ The Empty Keg BBS emptykeg.synchro.net:82 Lake Echo NS Canada

Re: Re: Raspberry Pi GPIO
By: Mortifis to MRO on Mon Dec 10 2018 10:38 am

where do you get your 3.3 number? the chart i am

looking at on the

internets sez whites are in that range and greens are

2-2.3

i can check out leds at work and see what the specs

are.

From here as well as other sources. Just curious which

resistor I should

use.

https://www.petervis.com/electronics/led/led-resistor-

calculator.html

i'm looking at digikey. there's a standard led here and the

green one is

spec'd at 2.1-2.6

go on digikey and look up the datasheets
it's important to know what you are working with

I agree that's why I posted the question, thank you for your
responses

---
■ Synchronet ■ The Empty Keg BBS emptykeg.synchro.net:82 Lake Echo NS Canada

On 12-10-18 10:38, Mortifis wrote to Vk3jed <=-

From here as well as other sources. Just curious

which resistor I

should use.

https://www.petervis.com/electronics/led/led-resistor-

calculator.html

I happen to still agree with MRO, I think that site is

wrong, but only for

the green LED, the other values look reasonably accurate.

... An aphrodisiac and a floor wax?
--- MultiMail/Win v0.51
■ Synchronet ■ Freeway BBS, Bendigo Australia.

freeway.apana.org.au

Thank you, I appreciate it, just wanted to clarify since I
have seen conflicting values for green lads

---
■ Synchronet ■ The Empty Keg BBS emptykeg.synchro.net:82 Lake Echo NS Canada

On 12-10-18 21:16, MRO wrote to Vk3jed <=-

also COLOR is spelled wrong!

Bloody Americans. :P


... *}- <- Tribble Olympics: Archery
--- MultiMail/Win v0.51
■ Synchronet ■ Freeway BBS, Bendigo Australia. freeway.apana.org.au

On 12-11-18 10:53, Mortifis wrote to Vk3jed <=-

Thank you, I appreciate it, just wanted to clarify since I
have seen conflicting values for green lads

You're welcome. Goes to show you can't trust everything you read on the Internet! :)


... Can anybody think of a good tagline I can steal?
--- MultiMail/Win v0.51
■ Synchronet ■ Freeway BBS, Bendigo Australia. freeway.apana.org.au

On 12-10-18 21:15, MRO wrote to Mortifis <=-

i'm looking at digikey. there's a standard led here and the green one
is spec'd at 2.1-2.6

Yep that makes sense.

go on digikey and look up the datasheets
it's important to know what you are working with

Datasheets are the best source. :)


... Confidence is the feeling you had before you knew better.
--- MultiMail/Win v0.51
■ Synchronet ■ Freeway BBS, Bendigo Australia. freeway.apana.org.au

Vk3jed, to Mortifis...

... Can anybody think of a good tagline I can steal?

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Like that one above?

-jag
Code it, Script it, Automate it!

... Don't you just love a tag line that references itself; like this one?
--- MultiMail/DOS v0.51
■ Synchronet ■ the Outwest BBS - outwestbbs.com - Email denn@outwestbbs.com

On 12-11-18 17:44, Jagossel wrote to Vk3jed <=-

@VIA: VERT/OUTWEST
Vk3jed, to Mortifis...

... Can anybody think of a good tagline I can steal?

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Like that one above?

Hahaha, indeed. :D


... Try this chicken. It tastes just like rattlesnake.
--- MultiMail/Win v0.51
■ Synchronet ■ Freeway BBS, Bendigo Australia. freeway.apana.org.au