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LED Hook Up

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Max_Powers96

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How Would i go about hooking up LEDs to my Car's Dome light?/Or Hooking up LEDs using Power coming from my car or any abundant power souce
 
The led must be the right way round and a resistor to limit the curent tugh the led.Use the Ohoms law to caculator the resistance (3 mA trugh the LED sod do)
 
RonH said:
And you'll need to reduce the voltage from 14v to 5, try a voltage divider.

Ron

You won't need a voltage divider as such. All you need is a resistor. Example:

A typical Blue LED

https://www.mouser.com/index.cfm?ha...ductid=415174&e_categoryid=90&e_pcodeid=64500

They tested it at 3.5V, 10mA. This means that we want that across it. Let's assume a 14V power supply coming in.

Vresistor = 14V - 3.5V = 10.5V dropped across the resistor

R = Vresistor / I
I = 10mA from above

R = 10.5/10mA = 1.05kohm

you would just need to hook this up in series, and you'd be good to go.

Edit: Another thing I thought I'd mention. In this configuration, the resistor would be dissipating I^2*R =~ 0.1W. A 1/4 watt resistor would be satisfactory. If you were to use an LED with more current, you might have to step it up to a 1/2 watt resistor.
 
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