I have a collection of 3 mm and 5 mm LEDs.
The colors are: Red, Blue, Green, Yellow, White
I’m aware of the variation in Forward voltage for these LEDs (1.8 to 3.4 v).
I always wanted to be able to pickup an LED and just plug it into the breadboard where I need it and not be concerned about supply voltage, or current draw.
I realize the brightness is dependent on both V applied and current drawn. And current varies according to applied voltage and current limiting resistor value.
I thought about constructing a set of LEDs from each size and color with a current limiting resistor soldered in series with one of the LED leads so I could then just grab one and plug it in.
I also realize the choice of brightness of an LED depends to some extent on its purpose.
For example, if it is a simple indicator and it won’t be in brilliant sunshine or other bright light, the a brightness in the middle of its range would be sufficient.
Here we go: Is there a single value resistor for both voltages (3.3 & 5.0) and all 5 mentioned colors that will do the trick?
If so, what value is recommended?
If not, then perhaps a single value for each applied voltage without regard to LED color?
Or, do we break the colors into 2 sets (1 and 2) and ignore the applied voltage and use a resistor for Set 1 and another resistor for Set 2?
I thought I’d ask before I go through the extensive experimentation to discover if what I’d like is reasonably doable.
Yes, I think you can use the same resistor with all LEDs, it just needs to be a value high enough that is safe to use with all LEDs. But, as you mentioned, it will interfere with its brightness.
Check some tutorials about calculating the resistor values for LEDs. For example:
I did some investigating, and it turns out a resistor around 600 ohms will provide a reasonable amount of brilliance, for all 5 colors of LED (Red, Green, Yellow, Blue and White) at both voltages of 3.3 and 5.0.
I’m going to construct a set of indicator LEDs of each color using a resistor around the 600-ohm value.
The intensity level is of course, slightly different for some of the LEDs, but the difference doesn’t seem significant.