1. SOLAR LAMP WITH VARIABLE POWER SUPPLY AND CHARGER Presented by sk.shaheena Under the guidance of Jayanthi madam

2. CONTENTS: o AIM  PRINCIPLE  CIRCUIT DIAGRAM  WORKING  ADVANTAGES  DISADVANTAGES  CONCLUSION

3. AIM:  By utilizing renewable (non conservational)resources efficiently to produce electricity to meet our requirement.

4. Principle:  To produce electricity we are using solar panel.  For continuous power supply requirement battery is used.

5. Circuit diagram :

6. Working :  LM317 place a wider role in the circuit because it supplies constant supply irrespective of the solar panel.  Because during daytime it produce more electricity compare to the evening.

7.  The working of the circuit is simple. The output of the solar panel is fed to the circuit via diode 1N4007 (D3), which acts as a polarity guard to protect the solar panel.  For using the variable power sup-ply, flip switch S2 to ‘on’ position. Connect a multimeter across CON1 terminals and set the required voltage (say, 9V) using potmeter VR1. The 9V output will be available across CON1 terminals. For charging a Li-ion battery (used in mobile phones), flip switch S3 to ‘on’ position and use connector CON2.

8. Zener diode:  Zener diode used as regulator along with LM317.  Zener diode ZD1 provides 4.7V to charge the Li-ion battery. Using this circuit, you can charge a 3.6V Li-ion cell very easily. Resistor R13 limits the charging current.

9. Advantages :  Circuit complexity is less  Good economic investment  Saving electricity bills  Availability of continuous power supply  No need of purchasing solar energy  Easy to design

10. DISADVANTAGES :  Solar panel is costly.  It is not efficient in rainy seasons.

11. APPLICATIONS:  Used as inverter  Used for mobile charger  Used for lamps

12. CONCLUSION :  By using solar energy the power can be efficiently supplied to the future generations also.  By creating awareness among the people about solar energy we can able to save the electricity required for the industrial & agricultural purposes and all other fields.