Understanding LEDs

[Atomic_Sheep]

Referring to the attached spec sheet, I'm trying to figure out what all the values mean.

1.) What do "IF Typica (mA)", "VF Typical (V)", "IV Typical (mcd)" & "Max Continuous IF Max (mA)" mean? If I'm not mistaken, the IF Typical and continuous are simply the recommended and max continuous currents that any particular LED can take before you start running the risk of it blowing?

2.) Why are we given 5V, 9V and 12V options? I know current and voltage are inversely proportionate, so is this designed to simply prevent the need for people to have to get the calculators out?

I am however quite surprised that you can power the same LED with different voltages. Lower currents with higher voltages obviously, but never knew that!

 

[ChrisP58]

Referring to the attached spec sheet, I'm trying to figure out what all the values mean.

1.) What do "IF Typica (mA)", "VF Typical (V)", "IV Typical (mcd)" & "Max Continuous IF Max (mA)" mean? If I'm not mistaken, the IF Typical and continuous are simply the recommended and max continuous currents that any particular LED can take before you start running the risk of it blowing?

2.) Why are we given 5V, 9V and 12V options? I know current and voltage are inversely proportionate, so is this designed to simply prevent the need for people to have to get the calculators out?

I am however quite surprised that you can power the same LED with different voltages. Lower currents with higher voltages obviously, but never knew that!

There is no spec sheet attached, so I really can't answer Q2. But I'm not aware of any discreet Led that matches your description unless it has some extra circuitry inside it.

Generally, you feed LED's with a controlled, or at least limited, current. The typical forward voltage is just that, typical. The actual voltage an LED needs to turn on to a given brightness will vary a bit with operating conditions. Your current source should have enough 'headroom' to reach the maximum Vf at that current.

 

[Atomic_Sheep]

Apologies, forgot to upload it, uploaded it now, not sure why it's not popping up, hopefully it just takes some time.

 

[Atomic_Sheep]

Looks like I finally managed to load the file! Sorry for double posting but had to update the status update.

 

[jjw]

5V-12V columns just show suitable values for current limiting resistors.

 

[NorthGuy]

These are just calculated numbers. For example, for the first LED at 5V with VF of 2.3, 5-2.3 = 2.7V will drop on the resistor. To ensure recommended 15mA, you need 2.7V/0.015A = 180Ohm resistor.

 

[ericgibbs]

Looks like I finally managed to load the file! Sorry for double posting but had to update the status update.

hi AS,
Try some of the series resistor values shown in your image, using this Tool, its important to realise that LED values are quoted as 'typical'.
https://www.electro-tech-online.com/tools/led-series-resistance-calculator.php
E
EDIT: the image shows the calculations for the second LED of your posted list.