ELECTRONICS DEVICES AND CIRCUIT ANALYSIS

1. Academic Year : 2019 - 2020
II Year 3rd Semester
Electronic devices and circuits
RAGHU ENGINEERING COLLEGE
(Autonomous)
Department of Electrical & Electronics Engineering
PEDIREDLA SANJAY KUMAR
Case Study
On
Implementation of logic gates using diodes
Faculty:
Mr. LAL BABU
Associate Professor

2. AIM
Using diodes obtain the logic:
• Which gives low output only when all the inputs are low
• Which gives high output only when all the inputs are high

3. CONTENTS
INTRODUCTION
 Logic gates
 AND gates
 OR gates
 Diodes
 PN junction diodes
Logic gates using diodes
 AND gate using diodes
Software analysis
 OR gate using diodes
Software analysis
Applications
Disadvantage
conclusion

4. LOGIC GATES
 Logic gates are electronic devices.
 Logic gates are used compute a function on a two valued signals.
 The basic building blocks of digital circuits.

5. AND GATE
A basic logic gate that gives
 A high output only if all the inputs are high.
 A low output in other cases.

6. OR GATE
An OR gate is a basic logic gate that gives
 A low output only if all the inputs are low.
 A high output in other cases.

7. DIODES
 A diode is an electrical devices that transfers current it, only in one
direction. We use mostly PN junction diode and Zener diode.

8. PN JUNCTION DIODE
 P type has positive charge carriers.
 N type has negative charge carriers.
 In forward bias electrons flow from N type to P type.
 In reverse bias electrons flow from P type to N type.

9. AND GATE USING DIODES
 When both the diodes are open circuited then the current doesn’t
flow into the diodes and hence it floes through the LED and finally LED
glows indicating the output as 1.
 When both the diodes are short circuited then the current flows only
through the diodes and no current passes through the LED, it doesn’t
glow indicating the output as 0.

10. OR GATE USING DIODES
 When both the diodes are open circuited then no current flows
through the LED and hence LED doesn’t glow indicating the output 0.
 When the diodes are short circuited then the current flows through
the LED and hence the LED glows indicating the output as 0.

11. APPLICATIONS OF LOGIC GATES USING DIODES
 Diodes acts as a switch.
 It can also be used as a security lock.
 AND gate can be used in circuits where something should only activate
if it is powered by multiple sources.

12. ADVANTAGES
 They have ability to rectify noise from input.
 They are cheaper in cost.
 Switching time is faster than analog circuits.

13. DISADVANTAGES
 Logic circuits uses more energy than other circuits.
 Diode logic suffers from voltage degradation.
 For activation, logic circuits require power system i.e. portable or
battery power systems which are limited in power.
 Diode logic permits only OR gate and AND gate.

14. CIRCUIT DIAGRAM

15. SIMULATION

16. CONCLUSION
A simple diode LED based AND and OR gate are constructed. The output is detected with
the help of an LED. Various inputs were provided at the input and necessary output was
obtained depending upon the circuit.

17. REFERENCES:
 https://www.google.com/search?q=diodes&oq=DIODES&aqs=chrome.0.0l6.386
2j0j8&sourceid=chrome&ie=UTF-8
 https://www.google.com/search?q=GATES&oq=GATES&aqs=chrome..69i57j0l5
.4663j0j8&sourceid=chrome&ie=UTF-35
 https://www.google.com/search?ei=lHhXXdSvMrbgz7sPuLOYmAs&q=AND+GAT
E&oq=AND+GATE&gs_l=psy-
ab.3..0i67j0j0i20i263j0l5j0i131j0i67.54273.58847..59770...1.2..3.1207.8999.
5-4j4j3......0....1..gws-
wiz.....10..0i71j35i39j0i131i67.6oyJOLp4a4k&ved=0ahUKEwjUybOd_4jkAhU28
HMBHbgZBrMQ4dUDCAo&uact=5

18. THANK YOU