Content warning: Electronics question – LED resistors, boosts welcome
I pulled apart an LED bulb. I can't remember the lumens but think it was 200lm. I want to use the individual LEDs with an Arduino but don't know what resistor to use with each as I'm not sure how big a punch each one packs. The resistor for all 36 tiny LEDs is in the second photo – looks like [brown black black black red] to my eyes.
Any idea how I can calculate the resistor needed for one bulb please?
Content warning: Electronics question – LED resistors, boosts welcome
Did you get an answer? The basic idea is to use Ohm's law with a twist. The voltage drop across the LED is constant and depends on the color. Say you apply 5V to an LED with a series current limiting resistor, if the LED is green it will drop 2.2V. that leaves 2.8V dropped across the resistor.
Content warning: Electronics question – LED resistors, boosts welcome
phew! Oh yes, thank you for checking and for the thoughful reply.
Many answers in the replies said exactly this (note the post was nearly a year ago...I have since wired it all up, completed the artwork and exhibited it at three venues!) but much appreciated for taking the time.
Content warning: Electronics question – LED resistors, boosts welcome
Thank you for your kind reply. I'm still very new to Mastodon. It seems that the the number next to the reply arrow is not the number of replies. But if I touch the test of your post I'm taken to a different view where I see all the replies. That is confusing.
Content warning: Electronics question – LED resistors, boosts welcome
yes there are some things here that take some getting used to, and a few small bugs because Mastodon is non-commercial and it is up to users, not teams of paid testers, to report errors.
There are also other reasons you might not see replies on an old post. Eg:
1) Many people automatically delete old posts 2) Many people reply privately 3) Some people's instances may not be 'federated' with your instance
Content warning: Electronics question – LED resistors, boosts welcome
the third example above is one that can be hard to understand as a new user, but becomes easier over time. There are plenty of explanations online about federation but I learned mostly by just interacting on here and picking up meaning slowly.
George Albercook
in reply to Fionnáin • • •Content warning: Electronics question – LED resistors, boosts welcome
George Albercook
in reply to George Albercook • • •Content warning: Electronics question – LED resistors, boosts welcome
It is always a good idea to use a current limited power supply for testing.
I'm not an EE so only know enough ot cause trouble. Corrections welcome.
Fionnáin
in reply to George Albercook • • •Content warning: Electronics question – LED resistors, boosts welcome
Many answers in the replies said exactly this (note the post was nearly a year ago...I have since wired it all up, completed the artwork and exhibited it at three venues!) but much appreciated for taking the time.
George Albercook
in reply to Fionnáin • • •Content warning: Electronics question – LED resistors, boosts welcome
Fionnáin
in reply to George Albercook • • •Content warning: Electronics question – LED resistors, boosts welcome
There are also other reasons you might not see replies on an old post. Eg:
1) Many people automatically delete old posts
2) Many people reply privately
3) Some people's instances may not be 'federated' with your instance
Fionnáin
in reply to Fionnáin • • •Content warning: Electronics question – LED resistors, boosts welcome
And welcome to Mastodon!
George Albercook
in reply to Fionnáin • • •Content warning: Electronics question – LED resistors, boosts welcome