LED Hook Up

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)

And you'll need to reduce the voltage from 14v to 5, try a voltage divider.

Ron

RonH said:

And you'll need to reduce the voltage from 14v to 5, try a voltage divider.

Ron

Click to expand...

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.

Thanks very much for your help.