1. Presentation Topic
4 Way Traffic Lights

2. Traffic lights Traffic lights, which may also be known as stoplights
Signaling devices positioned at road intersections
Use of lights in standard colors (Red ,yellow, Green)

3. Working of Traffic Lights
Illumination of the red signal prohibits any traffic from proceeding.
Yellow light denoting if safe to, prepare to stop short of the intersection.
Green light allows traffic to proceed in the direction denoted.

4. Technology Traditionally, incandescent and halogen Bulbs were used.
Light pattern of an LED array can be
Comparable with the pattern of an
incandescent or halogen bulb.

5. One way Traffic lights

6. 4 way traffic Lights

7. Basic components of traffic light system

8. 555 IC
The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications.

9. Operating Modes Monostable mode: Functions as a "one-shot".
Astable mode: free running mode:
Operate as an oscillator.
Bistable mode:
Operate as a flip-flop

10. 555 Timer Astable Multivibrator Circuit
555 timer IC is configured to function as an astable multivibrator.  An astable multivibrator is a timing circuit whose 'low' and 'high' states are both unstable. 
‘Pulse generator' circuit.

11. 4017 IC
The 4017 IC is a 16-pin chip.
Takes clock pulses from the clock input, and makes one of the ten outputs come on in sequence each time a clock pulse arrives.

12. Zener diode
This type of diode provides a stable reference voltage; this is a very useful type and is used in vast quantities.

13. Light Emitting Diode (LED)
It is one of the most popular types of diodes.
When this diode permits the transfer of electric current between the electrodes, light is produced.

14. Capacitors Store an electrical charge In timer circuits.
A capacitor may be used with a resistor to produce a timer.

15. Resistors Determine the flow of current in an electrical circuit.
High resistance in a circuit the flow of current is small, where the resistance is low the flow of current is large.

16. Battery
An electrical battery is a combination of one or more electrochemical cells, used to convert stored chemical energy into electrical energy.

17. Vero board
Veroboard is designed primarily for hard wiring of discrete components.
Manufactured from copper clad laminated boards which have been pierced with a grid of holes and machined to provide parallel tracks.