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The soldering will probably have some resistance, so the resistor might not be needed.
I'm powering an infrared led with a forward voltage of 1.2 volts and a forward current of 100mA from a AAA battery. The LED calculator said I should use a resistor of 3.3 ohms. Do I really need a resistor if the resistance I'm supposed to use is so low?
Quote from: Jdog on April 03, 2009, 08:51:16 PMI'm powering an infrared led with a forward voltage of 1.2 volts and a forward current of 100mA from a AAA battery. The LED calculator said I should use a resistor of 3.3 ohms. Do I really need a resistor if the resistance I'm supposed to use is so low?Your math is wrong. Assuming 6V, I calculated 48 ohms.What voltage are you powering the LED with? Are you sure its 100mA, because that's a lot for an LED!
i do agree on the 100ma being a bit much for an led tho.
fine then, go. hook your led up directly to your battery and watch as it burns out faster than normal! lol not really but you can have it hooked up to a battery directly it will just burn out a bit faster than normal.
Your math is wrong. Assuming 6V, I calculated 48 ohms.What voltage are you powering the LED with? Are you sure its 100mA, because that's a lot for an LED!
If you instead use two cells and a Constant Current circuit, you will have a controlled current for the entire life time of the battery.Btw. Why do you want to just have an IRLED light?