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Resistors Answered

Ok, I want to have a thing where ive got a battery pack, and then 3 toggle switches and one button switch, each one that is flipped/pushed lights up an LED and then the last one (button) lights up both the led and powers a small hobby motor or something like that. My question is, What do I need resistor-wise? (quantity, location, strength..)

Thanks!

Amendment I want to have the same idea going, but kind of have an extension cord running through it, so I plug the box in, and then plug something into a cord coming from the box.

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Brennn10

11 years ago

Well your resistor solely depends on the amount of voltage coming from the batteries and the the amount of voltage the LED can handle. Are you wiring this is series or parallel?

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LasVegasBrennn10

Reply 11 years ago

Actually, the resistor is dependent on the current rating of the LED. It's there to prevent overdriving and frying the LED. I've seen 3v LEDs connected to 120v with an appropriate resistor to limit the current. You calculate the resistor based on the voltage used and the current rating of the LED. IE: 120VDC / 30mA = 4Kohm Resistor.

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WeissensteinburgBrennn10

Reply 11 years ago

I think parallel, my conflict is that one resistor would limit the final motor/whatever, so would i need to spilt the wires, and then have a resistor for each led? Im installing a diagram program now, and ill put up one for my plan.

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Weissensteinburg

11 years ago

I'm not sure yet..but can you answer this: Does the resistor go on the + or - wire? If i want to power (pulling a number out of my head..obviously not correct) two leds that require 2volts, would i just use a 2volt resistor?

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Brennn10

11 years ago

What is your source voltage and the forward voltage for the LED?