Since I haven't dealt with voltages/current/etc since highschool, I'm not super confident in my abilities to not blow up a bunch of LEDs - I read a few guides, but would appreciate if someone could confirm I'm on the right track!
I'm using two 9v batteries adding up to 18v to power the system, and running 10 LEDs in 5 groups (2 2.2v, and 3 3.2v). The total voltage adds up to 14v, so my logic follows that if I use Ohm's Law on the two groups running 2.2v at 20mA, I need a 100 Ohm resistor on both to eat up the remaining 4v (2/0.02 = 100).
Would I be correct in my logic, or is there something I'm missing? Any guidance would be very appreciated!