mjrodg3n88 posted:1. 20mA = brighter LEDs
Yes. Remember, we're dealing with a range of values. The higher the current to the LED the brighter it will shine. But 20mA is the limit. Beyond that is outside the LED specifications.
2. Higher current (20mA vs 10mA) produces? a larger wattage. That is why 20mA requires a 1/4W resistor and 10mA a 1/8W. Correct?You are correct.
3. Using the calculator (shown in the image):
a. With a current of 20mA, the circuit's total current consumption = 18.5mA. If my power source is 12VDC 1A, then technically I could fit 54 LEDs on that
power source (1000/18.5 = 54.054054). With a power source of 12VDC 2A, I could double that to 108 LEDs (2000/18.5 = 108.108108).
b. With a current of 10mA, there is less of a current consumption, therefore allowing more LEDs on one power source (whether it be 12VDC 1A or 2A)Correct again. The 18.5mA value comes from our desired 20mA current that is limited by the standard resistor value from 435 ohms to 470 ohms. With ohm's law we get: V/R = I or 8.7 / 470 = .0185A. So the actual current is a bit less than what we are aiming for.
The number of LEDs is just a straight forward division of available amperage from the power supply to the amperage consumed by the LEDs. But be aware that the ratings of a power supply may not be very exact.
Does it seem like I am in the ballpark here of understanding, or am I way off?I'd say that you've got the right idea!
