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To make it easier to see which is positive - anode, and which is negative - cathode.
You need to know that, because the LED will only light if the positive and negative
terminals of the battery are connected to the correct sides of the LED.
Wiki User
∙ 9y ago
Wiki User
∙ 13y agoTo easily identify the anode and cathode. LEDs also have flat side, to identify the cathod.
LED -
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cathode anode
Wiki User
∙ 7y agoEntirely an issue of packaging and intended purpose.
Remember the actual LED inside these packages is a tiny chip of semiconductor material (often too small to see without magnification), usually all roughly the same size and the "LED" that you see may be anywhere from one to many millions of these tiny chips packaged together. The exception to this is the OLEDs, where the organic semiconductor material that the LED is made of can often be painted onto a flexible surface and a single OLED may cover several square feet of area (depending on intended use).
Wiki User
∙ 14y agoIt differentiates the positive from the negative pole on the LED. I do not know which is which, somebody help on this one.
Wiki User
∙ 9y agoPositive rerminal
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Trying to make some indicators for a bike and am going to use 1.5 volt leds and a 12 volt 11ah battery by putting 8 leds in series was wondering whether resistors are needed not to short the leds?
Resistors will be needed in all cases when driving LEDs from a voltage source, unless you are using LEDs that already have a built in current limiting IC inside the package (a few do these days, for example I have some blinking LEDs that need no resistor they have a blinker IC built in that also limits current).However you have another problem that you obviously are not aware of. 8 LEDs rated at 1.5V in series totals exactly 12V. But your battery is only rated at 12V. As the battery discharges its voltage slowly drops, the moment it drops under 12V all the LEDs will turn off! I strongly recommend that you use no more than 7 LEDs rated at 1.5V in a circuit powered by a 12V battery, so that the battery can actually gets a chance to discharge beyond its knee voltage. In this case the resistor will drop the remaining voltage, whatever it is depending on the charge state of your battery.
How are LED TVs made?
by growing an array of different color LEDs and driver transistors on a glass sheet. each pixel gets a square array of 4 LEDs: red, green, blue, green. the glass sheet is then wired to the TV circuits. the glass sheet (screen) is effectively a super giant IC.
What is the lumen loss of led lamps?
LEDs will typically reduce their light output throughout their life after an initial increase above the rated light output.This degradation will usually be a near-linear reduction.Well-made LEDs will not normally fail catastrophically, but drop in their output until they are no longer useful.High quality LEDs are typically rated to drop to 70% of initial light output after 50,000 hours for white LEDs, and 100,000 hours for all other colours.
Can a nokia bl-5j 3.7 volt battery be used to power LED's safetly and how?
A: It sure can but what is voltage iof the LEDS 3.2 V then you need to drop 3.7 to 3.2 v at ~20ma .5v / 0,02=27 ohms in series the LEDS are 1.8 you need 3.7- 1.8/.02= 100 ohms in series. The warning is the life of this setup is going to be short lived after the battery drain off the battery needs recharging if so it is better to supply the LEDS from the charger directly will last until the LEDS QUIT FUNCTIONING
What are the types of LED?
There are a number of major types of LED which are available and being developed. These LED types are summaries below.Traditional inorganic LEDs: This type of LED is the traditional form of diode that has been available since the 1960s. It is manufactured from inorganic materials. Some of the more widely used are compound semiconductors such as Aluminium gallium arsenide, Gallium arsenide phosphide, and many more.These LEDs are typified by the small LED lamps that are used as panel indicators, although there are very many formats for LEDs of this type. However even within the in-organic LED category, there are many different styles of LED:Single colour 5 mm, etc - the very traditional LED packageSurface mount LEDsBi-colour and multicolour LEDs - the types of LEDs contain several individual LEDs that are turned on by different voltages, etc.Flashing LEDs - with a small time integrated into the packageAlphanumeric LED displays. . . . . more . . . .All these different types of inorganic LED are used in very large quantitiesOrganic LEDs: Organic LEDs are a development of the basic idea for the light emitting diode. This type of LED uses organic materials as the name indicates.The traditional types of LED utilise traditional inorganic semiconductors with varying dopant levels and they produce light from the defined PN junction - often this is a point of light. The organic type of LED display is based on organic materials which are manufactured in sheets and provide a diffuse area of light. Typically a very thin film of organic material is printed onto a substrate made of glass. A semiconductor circuit is then used to carry the electrical charges to the imprinted pixels, causing them to glow.High brightness LEDs: High brightness LEDs, HBLEDs, are a type of inorganic LED that are starting to be used for lighting applications. This type of LED is essentially the same as the basic inorganic LED, but has a much greater light output. To generate the higher light output, this LED type requires to be able to handle much higher current levels and power dissipation. Often these LEDs are mounted such that they can be mounted onto a heatsink to remove the unwanted heat.In view of their greater efficiency, this type of LED is being seen as a replacement for incandescent and the various other forms of energy saving or energy efficient lights such as the Compact Fluorescent Lightbulbs, CFLs. The HBLEDs have a greater efficiency level and they also have a longer life, especially when being switched on and off many times. Coupled with their instantaneous transition to full light output, this type of LED is being seen as the way forwards for lighting applications.
How are LEDs different from other artificial light sources?
The difference is that LEDs use less electricity.
What is the length of a pair of scissors?
They can be different lengths. YOU say they can be shown in different lengths but i need to know what particular lengths
What is the triangle that has two different lengths?
A SCALENE triangle has all three sides different lengths.
What makes up the lights of a set of traffic lights?
Incandescent light bulbs are used, in addition to LEDs. LEDs or laser emitted diodes, produce the different colours with different electricity molecules mixing with the oxygen in the air
What are the lengths of the sides of an obtuse triangle?
The 3 sides have different lengths
Which is a more powerful light - 95 leds or 128 leds?
If your compairing apples to apples like 3 watt leds to 3w leds then 128. The more leds the higher the power.
How long was each episode of fawlty towers?
There were 12 episodes of Fawlty Towers. Series 1, six episodes first broadcast on BBC television in the UK weekly from 19th September 1975. Series 2, six episodes broadcast weekly from 19th February 1979.
Lengths of a scalene triangle sides?
All three sides have different lengths.
Why do we have varying day lengths?
The tilt of the earth causes different day lengths.
Why germanium and silicon are not preferred in LEDs?
A: Because the element has different property as gallium arsenide.
How much energy does a led use per hour?
LEDs come for different power ratings. Miniature LEDs use between approximately 40-90 mW. High-power LEDs - used for illumination - can use hundreds of watts per square centimeter.
How many lengths do you swim for a gold?
That does not matter. There are different events which consist of different lengths. You just have to place 1st in an event.
