How to calculate how to choose a resistor <resistor> ???

I am an amateur :)

I was looking for it on the Internet, but everywhere there are some answers for professionals, I do not understand See how it is calculated, which resistor should I choose for a given voltage.

I know that for 12V cars we use a 560ohm diode

CLICK

That should help you

Hello

R = U / I
U = R * I
I = U / R
R-resistance in ohms
I is the amperage in A
U-voltage in volts

So, if you have a 12V battery, your led needs about 0.01-0.02A amps,
the power supply is subtracted from the voltage of the proper operation for the diode:
12V (supply voltage) -2.4V (diode voltage for the yellow diode) = 9.6V

Now for the formula:
R = U / I
R = 9.6V / 0.02A
R = 480om

The discrepancy is because you were probably calculated for the current of 0.01A, I usually do the average of 0.015A or it was calculated for a different diode voltage (different color )

For a series connection, the diode voltages add up, and for a parallel connection, you add up the currents.

You can find the tensions for a given color in my post https://www.elektroda.pl/rtvforum/topic671136.html
Third topic from the end :)

If you have any other questions, I will be happy to answer

Macieks14 wrote:

R = U / I
U = R * I
I = U / R

the power supply is subtracted from the voltage of the proper operation for the diode:
12V (supply voltage) -2.4V (diode voltage for the yellow LED) = 9.6V

Now for the formula:
R = U / I
R = 9.6V / 0.02A
R = 480om

Thanks a lot, that's enough, but let others add their own methods :)

And now some questions:

-You can also calculate I and U ???

-To calculate the resistance, we need to know the voltage 'U' which is the power supply - the diode voltage


- What is the significance of amps and do they have any greater influence on the luminance, can it be omitted and it is enough to know only the value of I

Do you still have the strength to explain 657 how to choose a resistor for the LED?
There were dozens of such topics ...
Everything is here: https://www.elektroda.pl/rtvforum/topic490262.html " target="_blank" class="postlink inline" title="" > https://www.elektroda.pl/rtvforum/topic490262.html :!:

Why is this topic still in the bin?

PS
Author of the topic.
The unit of current intensity is Ampere. The current in the diagrams and formulas is marked with the letter I. So the value of the current I is expressed in amperes A. Like the amount of water in liters, weight in kilograms, length in meters. The child would understand.
And the amperage is critical to the brightness of the LED.

Hello

Here you have color-dependent voltage for the LEDs
Red and infrared 1.5V
Yellow and green 2.5V-3V
Blue and white 3.4V-3.6V

Remember you always subtract the supply voltage from the diode voltage

Macieks14 wrote:

For a series connection, the diode voltages add up, and for a parallel connection, you add up the currents.

So 12V is the power supply and 2.4 is the diode voltage !!!