Have a string of LEDs in series and I used a resistor calculator to find the resistor needed for it to work properly with my 14 volt input. However each led has forward current of 100ma and I'm not sure if I have to worry about the input amperage. I'm using a ac/12vdc adapter that states it puts out 150ma and I don't know if that divides equally over the LEDs like voltage. Will this work?

If the LEDs are in series then the same current flows through all of them, so its not an issue. Current divides only if the circuit divides - such as wiring the LEDs in parallel - which is not what you're doing.

How many LEDs are you wiring, and what resistor value did you come up with? I think it should be around 150 ohms, right?

Thanks, the input voltage is actually 15.7 and I have 10 LEDS
Wavelength:
890 nm

Angle of Half Intensity:

±22 °

Intensity:

70 mW/cm2

Forward (Drive) Current:
100 mA

Forward Voltage:

1.4 V



So I'm using a 18ohm 1/2 watt resistor, correct? Do I have to worry about what amperage the input is because I have some other adapters as well. One of which is 300ma. I just want to be sure I don't burn them out. The amps is the part I don't have a full understanding on.

I think 18 ohms is too low: 15 volts/18 ohms = 0.887 A, which will blow out the power supply. Given that you want 100mA the resistor should be 15.7 V/0.1A = 157 ohms. The power rating of the resistor is i^2R = 0.1^2 x 157 = 1.57 W.

my understanding of that formula is to divide the leftover voltage by the .1A as in 15.7 V- (10x1.4 V) / .1A = 17 ohms. I got that from 2 sites, one of which is How to make LEDs glow not blow! | Let's Make Robots!
are they wrong?

Yes, that will work. I didn't realize you had the forward voltage rating for the LED - my bad.