If a multicolour LED is switched fast enough between two polarities, the LED will produce a third colour.Ī red/green LED will produce a yellow light when rapidly switched back and forth between biasing polarities. It works using a semiconductor that is manipulated to have positively charged atoms, meaning there are spaces without. Multicolour LEDs are typically r e d when biased in one direction and green when biased in the other. Note that the direction of device current has reversed and is now passing through the right pn junction. When Light Emitting Diode (LED) is forward biased, the free electrons from n-side and the holes. ( ii), the pn junction on the right will light. Light Emitting Diode (LED) works only in forward bias condition. If the polarity of the voltage source is reversed as shown in Fig. Note that the device current passes through the left pn junction. ( i), the pn junction on the left will light. If positive potential is applied to the top terminal as shown in Fig. The semiconductors used in LEDs can relax excited electrons moving from negatively-charged cathode to positively-charged anode by shedding photons and very little heat. they are in parallel with anode of one being connected to the cathode of the other. In order to explain how an LED works we must explain the four main components of an LED lamp the LED Chip, the Driver, the The LED chip emits lights the in. Multi Color LED’s actually contain two pn junctions that are connected in r everse-parallel i.e. One commonly used schematic symbol for these LEDs is shown in below figure. A LED that emits one colour when forward biased and another colour when reverse biased is called a multicolour LED.
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