So, I was going through the spec sheet of super bright 5mm orange LED, and it was listed that the forward voltage is between 1.8V and 2.5V. Below that there was a property listed as 'typical voltage' and had a value of 3.2V. I'm confused as to what value of resistance I must use.
Electronic – LED typical and forward voltages
diodesledresistancesemiconductorsvoltage
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I'd suggest a surface mount LED and some glue. They are available in sizes from almost-to-small-to-see up to huge-enough-to-be-used-for-a-car-brake-light. Also available in any color you want. Here are some smaller varieties:
You might attach small wires directly to the LED, or attach the LED to a small PCB and attach wires in turn to that. Or, you might make a one-off PCB with some copper-clad board and a razor blade. Depends on where you want the wires, and what your production methods are, I suppose.
Another possibility is to mount the LED behind the panel, and bring the light through the panel with a hole or a lightpipe. See this page from the Mouser catalog for some ideas.
There are also square LEDs that will fit in that space nicely, which could be mounted simply by cutting the right sized hole. Then either glue it in place, or stick some perfboard on the backside of your panel, and solder the LED to that to hold it in place. If you must have a replaceable LED, you could probably find a way to mount a header behind the panel, and shove the LED leads into it, and friction will be enough to retain the LED if you don't have extreme vibration.
For your simulation, you specify the led's forward voltage as "3V at 1A". This means the forward voltage of the leds at about 20mA will be much lower.
Everything is right there, you just need to read the leds datasheet to find the forward voltage at arount 20mA.
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Best Answer
The important thing to realize is that CURRENT is what MATTERS to an LED. The voltage is given as a range because the voltage varies, depending on manufacturing tolerances, temperature, etc.
If you design well for LEDs, you feed them with a current source, and the voltage simply needs to be adequate for the number of LEDs you have in series on each current source. In figuring the voltage compliance your current source should have, look at the highest voltage quoted.
If you use resistors for current-limiting LEDs, use either the LOWEST value of forward voltage provided, or a bit less than that (safety margin) when choosing a resistor to set the current. This is sub-optimal .vs. a current source, as it will generally be providing less than the maximum safe current in order not to provide more than the maximum safe current under conditions (or for parts) where the forward voltage is particularly low.