I recently came across a finding I don't understand: 100mw power dissipation for a (4) LED circuit. I don't have a problem with the power value itself (100mw) but the recommendation to go with 1 Watt power instead of 1/2w or even 1/8w. Should the rating be changed from 1mw resistor to something else? My understand is that the maximum power per resistor should not exceed Power x 2, for example .04 x 2 = .08( < .25) is covered by resistor with .25power and up.
Number of LEDs | 4 |
Supply voltage, Vs | 5V |
LED forward voltage, Vf | 1.25V |
LED forward current, If | 20mA |
Individual Diode Power Dissipation | 25mW |
Total Diode Power Dissipation | 100mW |
Recommended Resistor Wattage | 1 Watt Resistors |