LEDS for Dummies : pay attention class !

CFD125

Ok, I know there are other people out there with the same question and I am a little old school and ignorant of the subject.

What in the world are you refering to when you state that an LED is "passive". Does that mean that it has to be synced with another? Much like an old Visibar only uses one motor to turn two rotators?

Also, I have seen ads on this forum for Talons and the frequent question is "Are they the ballast version?" Why would a low current drawing LED need to use a ballast, and "Ballast version" as opposed to what?

And remember folks: I am not as think as you dumb I am Confused

Hey someone has to ask...

whackersanonymous

Basically it requires a ballast to activate the LED.

jarthur

Ballast LED heads require just that, a ballast to supply extra power for them, they also do make some noise (generally noticeable with dash lights like the old talons).

Passive modules all you need is a 12v (or whatever the head is spec'ed to) power and the light will operate.

Now a sub category in both of these are the drone light heads. The majority of led heads on the market are "smart" and include internal flashers that can usually be synced to other LEDs of the same style or manufacturer.

Drone heads are essentially dumb, they have no flasher or sync capabilities on their own and generally just have the two power wires that then connect to a flasher in the unit that they are apart of, or one separately. You most often see these heads in lightbars, TA's, warning sticks, multiple head dash lights and the like.

ukr

Ballast driven lightheads need a much higher voltage to operate, since all leds are connected in series. They will not light up on 12V power source / flashers.
The ballast provides the proper voltage and regulates the current for the whole lighthead. The Ballast also recognizes what type of lighthead is connected (how much voltage must be provided)

A passive lighthead uses groups of 2, 3 or 4 LEDs in series so they can run at 12V. Each group has its own current regulator integrated in the lighthead.

Pimpala03

The Ballast model is the old original ones that make a ticking/whining/cricket noise while operating. These models were discontinued due to them causing RF interference.

The new Passive versions are silent and cause no interference. They also say PASSIVE on the label.

Some say that one version is brighter than the other while others disagree.

cell2solutions · Regular Joined: 26 Mar 2007 Posts: 368 Location: Spain

Some basic info -

The electrical characteristics of LEDs?
A typical LED has a forward voltage rating between 2 and 4 Volts. The red, yellow, and orange types have a forward voltage around 2 Volts, while the blue, white, and true green types have a forward voltage around 3.3 Volts. The typical drive current for LEDs is 20 milliamperes (mA).
From this you can see an LED uses a modest amount of power, a few tens of milliwatts compared to the few tens of Watts an incandescent bulb uses. In other words, the power used by an LED is one thousandth of that used by a familiar light bulb. Since an LED is a diode, even after it ceases to
produce light, it will still use power, and if connected with other LED’s in series should allow the others to continue working.

Why white LEDs cost more.
The manufacturing process to create white is to combine red, green, and blue colored Phosphor. When you get the right mix, the effect is white light. This is the same way your television works, the white object on the screen is really depicted using dots of red, green and blue lit up in
proportions that form an impression of white, hence the cost of the white LED is governed by this expensive manufacturing process. Some whites depicting a blueish (Cool White) or yellowish (Warm White) tinge are the product of the outer edges of the pure white material and are sold off for torch lights and decorative lights, however inferior quality manufacturers will try to use these for automotive lighting because they are less expensive.

Be wary of ‘’Hot’’ LEDs
LEDs have a reputation for long life, but they are also easily abused. Light Emitting Diodes are more fragile than most people are aware. Electrical or thermal deficiencies in their circuit board design will often cause a sudden failure. Too much current or too much heat for example, could result in a 100,000 hour part lasting only 100 hours or less. Quality manufacturers have specifications that represent the typical operating voltage curve of the LEDs. Driving the LEDs above that point will shorten its life. There is also a maximum rating for either current or forward voltage, exceeding those ratings will dramatically shorten the lifespan of an LED. Driving an LED “hot” will make it burn more brightly for a shorter time. If the area of an LED feels hot, the LED is being overdriven. Heat from an LED is not easily managed and LEDs must operate below 85 degrees Celsius. High quality, high output LEDs can provide 80% of their original illumination
output at 100,000 hours, if they are not abused.

LFD-Mike

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