Opto Electronics – Notes – 1

1. Optoelectronic devices either produce light or use light in their operation.

2. A Light−Emitting Diode (LED) is an optoelectronic device that, when forward biased, produces visible light. The light may be red, green, or amber, depending upon the material used to make the diode.

Figure-1 : Symbol for LED

3. The life expectancy of the LED is very long, over 100,000 hours of operation. For this reason, LEDs are used widely as “power on” indicators ofdigital voltmeters, frequency counters, etc. and as displays for pocket calculators where they form seven−segment displays.

Figure-2 : LEDs arranged for seven segment display

4. Laser diodes are LEDs specifically designed to produce coherent light with a narrow bandwidth and are suitable for CD players and optical communications.

5. A photodiode is another optoelectronic device which receives light and converts it to electrical signals. Photodiodes respond quickly to changes in light intensity, and for this reason are extremely useful in digital applications such asphotographic light meters and optical scanning equipment.

Figure-3 : Symbol for photodiode

6. A photocell is an older device that uses light ina way similar to the photodiode. Photocells are used in various types of control and timing circuits as, for example, the automatic street light controllers in most cities. 

Figure-4 : Symbol for photocell

7. A solar cell is another device that converts light energy into electrical energy. A solar cell acts much like a battery when exposed to light and as with batteries, solar cells may be connected in series or parallel to produce higher voltages and currents.

Figure-5 : Symbol for solar cell

8. Solar cells find widespread application in communications satellites and solar−powered homes. 

9. An optical coupler, sometimes referred to as an optoisolator, consists of an LED and a photodiode and each of these devices are isolated from each other. Isolation between the input and output is desirable because it reduces electromagnetic interference. Their most important application is in fiber optic communications links.

Figure-6 : An optical coupler

Opto Electronics – Mcq
Opto Electronics – Notes
Opto Electronics – IQ

Be a Part of The New & Next

MCQs fb  MCQs G+

Share the Knowledge

GATE Total InfoGATE 2019 BooksFree Notes
IES Total InfoIES 2019 BooksFree Mock tests
JAM Total InfoJAM 2019 BooksEngg Diploma
PSUs Total InfoM Tech Total InfoUGC NET Total Info

General Knowledge Books

McqSeries.com is an online forum for multiple choice questions. This forum would be really-really helpful for those candidates who are preparing for examination conducted by Union Public Service Commission (like Civil Services Examination, Engineering Services Examination, Special Class Railway Apprentice, National Defence Academy, Combined Defence Services, etc.), Staff Selection Commission (like Combined Graduate Level, Junior Engineer, Food Corporation of India etc.), various public sector units (like DRDO, DMRC, BARC, BSNL, ONGC, etc.), Graduate Aptitude Test in Engineering, Indian Institute of Technology Entrance Examination etc. and many other national and state level examination.

Leave a Reply

Your email address will not be published. Required fields are marked *

GATE, IES & PSUs Total Information & GuidanceCheck Here!
Copy Protected by Chetan's WP-Copyprotect.