LED Basics

LED lighting is not a new idea. It is only in the last few years or so that the technology’s efficiency and efficacy surpassed CFL and HID lighting. This makes it hard to find cost effective lighting replacement, without large upfront cost.  But at Eco Brooklyn we are passionate about improving the energy efficiency of Brooklyn brownstones and constantly tinker with the technology to see how we can use it in our building. So let the experiments begin!

LEDs are typically DC devices that can be powered either through a controlled Voltage or Current drive source. Voltage sources have to be stable. Any tiny fluctuation in voltage can cause a purportionally greater current spike. This translates into flickering lights.  On the other hand, Current driver circuits are expensive and yield low wattage, high efficiency configurations. This can cause an unreasonable cost associated with powering each led fixture.

To explain the difference between the two power source terms I will use a small analogy.  Think of electricity traveling through a wire as water through a pipe.

Voltage = ‘Pressure’ of electricity

Current = ‘Amount’ of electricity

If you happen to have a dead computer around then you might have a working voltage source. Your computer power supply can be converted into a stable voltage source with a high wattage rating. (Added benefits include built in protection against over voltage, short circuit, open circuit, temp, and just about anything else that could cause a safety issue. )

To drive an LED from a Voltage source you need to put a Resistor in series with the LED. This is a good way to create a simple stable voltage controlled current source.  What kind of resistor do I use? Well here is a calculator for figuring out your LED resistor needs. You will just need some of the information from your specific LED’s limitations.

http://led.linear1.org/1led.wiz

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