Windell said in a comment on the Larson Scanner kit that:

The forward voltage of typical red LEDs, i.e., the voltage at which they conduct about 20 mA, is roughly 2 V.

I have white LED's that pull 20mA at 3.2-3.4V according to what it says on the package anyways.

I'm not good with electronics in anyway and I hope to learn, but if the white LED's are pulling the same amount of current at a higher power, does that really mean I have to swap out the resistors that come in the Larson Scanner kit?

I'm not good with electronics in anyway and I hope to learn, but if the white LED's are pulling the same amount of current at a higher power, does that really mean I have to swap out the resistors that come in the Larson Scanner kit?

No, you don't have to swap out the resistors in the Larson Scanner kit. It will work fine with the red LEDs and resistors supplied.

You haven't said it directly, but it seems like you're thinking about building a Larson Scanner kit, but replacing the red LEDs with white LEDs. To do this and make it work, the most important change that you need to make is replacing the 3V battery holder (2xAA) with a 4.5 V battery holder (3xAA, or 3xAAA). The white LEDs won't run on 3 V.

Quote by: Windell

I'm not good with electronics in anyway and I hope to learn, but if the white LED's are pulling the same amount of current at a higher power, does that really mean I have to swap out the resistors that come in the Larson Scanner kit?

You haven't said it directly, but it seems like you're thinking about building a Larson Scanner kit, but replacing the red LEDs with white LEDs. To do this and make it work, the most important change that you need to make is replacing the 3V battery holder (2xAA) with a 4.5 V battery holder (3xAA, or 3xAAA). The white LEDs won't run on 3 V.

You're right. I am and I got that much, Windell, but if the White LED's pull the same power (20mA) as the Red LED's (you mentioned they also pull 20mA) I would not have to change the resistors, right? That's the main point I'm worried about.

if the White LED's pull the same power (20mA) as the Red LED's (you mentioned they also pull 20mA) I would not have to change the resistors, right? That's the main point I'm worried about.

Turns out that the standard resistors work fine for white as well. (The actual voltage drop needed is similar for red at 3 V and white at 4.5 V.) You can always use a larger resistor for longer battery life.

Quote by: Windell

Turns out that the standard resistors work fine for white as well. (The actual voltage drop needed is similar for red at 3 V and white at 4.5 V.) You can always use a larger resistor for longer battery life.

Awesome. I don't have to go finding a resistance calculator. Thanks!