Recent questions tagged led

Description : How to Build a Led Billboard

Last Answer : How to Build a Led Billboard How to Build a LED Billboard LEDs are basically light emitting diodes. They tend to emit light when an electrical power courses through them. A LED billboard is a ... plazas. China is one of the largest competitors in the global market for producing state of art LEDs.

Description : What are the advantages of LED lamps?

Last Answer : What are the advantages of LED lamps? LED lamps have an advantage over fluorescent lamps in the first place in terms of environmental friendliness. Another reason for using LED lamps is ... advantages. Today, such lamps are used in everyday life, for industrial lighting and street lighting.

Description : Advantages of LED over CFL.

Last Answer : Advantages of LED over CFL. 1) Efficiency: LED bulbs use close to a third of the amount of power CFL bulbs would use to produce the same amount of light. This makes them ... decorative to heavy duty industrial applications.  6) Maintenance: Smooth light and low maintenance compared to CFL

Description : Draw symbols of zener diode and LED.

Last Answer : Symbol of zener diode : Symbol of LED

Description : Analyze the effect of supply voltage on performance of LED as regards current, Lumen output, efficacy and life. 

Last Answer : 1) Effect on Current:- In LED current depends upon supply voltage, if voltage get changes then current also change but this change in current will be control by resistors which are connected in series.  2) ...   4) Effect on Life:- If supply voltage is not stable then life of LED get reduced. 

Description :  Compare the salient features of LED and CFL based on: i] Lamp Efficiency ii] Life span 

Last Answer : Parameter LED CFL Lamp Efficiency  High (more than 70 lumen per watt) Comparatively less (50-60 lumen per watt) Life span (in working hours) 10000 3000

Description : Why the Led Glow in Dc Supply ? Whenever give the Ac Supply What is Affect in Led ?

Last Answer : LEDs consume DC current to produce light; with AC current the LED will only be lit when current flow is in the proper direction. AC applied to an LED will cause it to blink on and off, and at high frequency the LED will appear to be lit continuously.

Description : Describe working principle of LED with diagram.

Last Answer : Constructional Diagram: * Light Emitting Diode (LED) works only in forward bias condition. When Light Emitting Diode (LED) is forward biased, the free electrons from ... gallium arsenide and gallium phosphide the emitted photons have sufficient energy to produce intense visible light.

Description : Draw the symbol of LED & photodiode. 

Last Answer : Symbol of LED & photodiode

Description : Draw symbol of LED and explain it’s working principle.

Last Answer : Construction of LED: The basic structure of LED is shown in fig.(a). The active region exists between the p and n regions. The light emerges from the active side in all the directions when electron hole-pairs ... fig.(c). In this way an LED emits light. This is the principle of operation of LED.

Description : List four applications of LED.

Last Answer : Applications of LED 1.As a power supply status indicator in electronics instruments 2.In traffic light Indicators. 3.In data displaying boards. 4.In medical applications and toys 5.In optical fiber communications 6.Remote controls

Description : How do you know the voltage of an LED?

Last Answer : After connecting led to a DC source we can measure the voltage of led by connecting a voltmeter across it.  But voltage rating of the led is given by the manufacturers. Or we can ... in the market For more doubts connect with me in linkdin [email protected] 

Description : What is the voltage of a red LED?

Last Answer : A red led requires 2v to light. LEDs requires different amounts of voltage ranging between 1.8 and 3.3 depending on the intensity and color of the Led.