that would be remarkable.. but I meant a person
I have noobish questions, and I was told about this chat in a comment on one of my questions
Anyway, if anyone could lend some advice it would be greatly appreciated. Basically, I got some cheap LEDs (forward voltage = 2.2V, forward current = 700mA). I also have an old PC power supply (3.3V, 5V, and 12V). I was playing around with some calculations and actually got an LED to light using a "current limiting resistor".
First I tried with just one LED and a 50 Ohm resistor, in series, attached to 5V rail on a breadboard
then I tried two LEDs in series (4.4V total) leaving 0.6 volts on the resistor.
Ultimately, I was hoping to design a circuit that minimizes the amount of power dissipating in the current limiting resistor, and the best I came up with was 5 LEDs in series (11V) with a single resistor, on 12V.
1V * 0.7A = 0.7W of power dissipated in the resistor.. I think..
vs. 0.6V * 0.7A = 0.42W of power (but for only two LEDS, instead of 5)
am I calculating efficiency properly, or are there other things to worry about in a design like this?