How do I connect 1 watt or 3 watt LED or higher on a 14v source (in my car).....I know that you can connect a low power LED(5 mm) using a resistor....but a high power LED like 1watt onward....you need a driver for it...is that necessary? why cant i just connect a Resistor by itself? ....how can i design a driver that can handle....LED @ 200mA, Vf: 3.6 - 4.2....power source: 12-14 Volt