The 5mm LEDs are encapsulated in a transparent colored resin dome whose utility is to protect the light emitter, it contains three pieces: reflector cup, semiconductor, and conductive wire. Two legs extend below this dome: the longest is of positive polarity and is called the anode, the shortest is of negative polarity and is called the cathode. These pins will indicate the way in which the LED should be connected to the circuit.

These diodes have dominated the high brightness LED market due to their highly reflective design with primary optics and their high brightness range (5,000 mcd). They generate a bright red (625nm) light, which makes them visible at long distances.
They can be used for lighting, posters, traffic lights, flashlights, signaling devices, information panels, medical applications, lighting of liquid crystal screens of mobile phones, calculators and electronic agendas, printers and bicycles, and various adaptations, among others.

How do they work?

LEDs can be used in three different ways:

• Individual: direct LED power from the power supply, either by means of a regulated source or with the use of resistors or regulators. The desired voltage must be supplied to the LED within the working values.

• Parallel configuration: powering a group of LEDs connecting all the anodes together and all the cathodes together, using the required voltage regulated by a single resistor in series.

• Series configuration: powering a group of LEDs connected sequentially. The number of LEDs to be used per series will be limited by the voltage delivered by the power supply. In most cases, a resistor is required to compensate for the differences in supply voltage per series of LEDs, being able to carry out different series in parallel with the same power supply.