Hello pals... I need to connect 2 LEDs to a circuit. They will be kind of parallel connection. But the problem is: whether to connect 1 resistor each for individual LED, or to just connect 1 resistor and let the LEDs share the resistance? Which is the better way?
2006-09-25 09:11:25 · 3 answers · asked by Say 1 in Consumer Electronics ➔ Other - Electronics
if in parallel then 1 for each LED. If you only use one, then when both come on, they will dim, or they will always both be either on or off. It depends on how you hook them up.
2006-09-25 10:04:00 · answer #1 · answered by justme 7 · 0⤊ 0⤋
There are two schools of thought on this.
One is that the LEDs can share the resistor, eliminating one very expensive (like 2 cents) component and save board space and cost. The dis-advantage is that you need a higher power resistor and there will be differences in light intensity's, especially with the cheaper brands of LEDs, because one will have a slightly lower on voltage and will hog all the current. The better solution is to use 1 resistor per LED.
2006-09-26 00:57:09 · answer #2 · answered by Aurthor D 4 · 0⤊ 0⤋
LEDs usually drop 1.2 volts, check your specs.
The resistor drops the voltage so you don't burn out your LED.
So, say you are using a 5 Volt supply, your LEDs take 30 milliamps each, that is a total of 60 milliamps you want running through your circuit. Since you want to drop (5-1.2)V or 3.8 Volts you can use the equation V / I = R so 3.8Volts / 0.060 Amps equals 63Ω Better use a resistor with a power level of 1/4 W or bigger for that. You can put the resistor on either the plus or minus leg of the LEDs
2006-09-25 10:06:53 · answer #3 · answered by Dennis K 4 · 0⤊ 0⤋