I'm trying to avoid extra "stuff" because of space reasons, so I'm looking at putting two LEDs in series. If I have two white LEDs* that operate on about 4V at 20 mA connected in series, using a 1 kOhm resistor at 12V, what rating does the resistor need to have?
Can I subtract the required voltage of the LEDS like this?
12V - 4V -4V = 4V
4V / 1000 ohm=.004A
.004A * 12V=.048W
Do I need to keep it in like this?
12V / 1000 ohm=.012A
.012A * 12V=.144W
*
Puckdropper
