The document details a project on automatic light control using a light-dependent resistor (LDR), NPN transistor, and LED. It includes information on the circuit diagram, working process, applications, advantages, and disadvantages, along with a breakdown of project costs. The system is designed for use in road lighting, home security, and other applications, providing benefits like power savings and automation.

1. W E L C O M E T O O U R
P R E S E N TAT I O N

2. Automatic Light Control Using LDR

3. • Circuit diagram.
• Equipment list with brief.
• Working process.
• Real time video of project.
• Application.
• Advantage.
• Disadvantage.
• Project Cost.
CONTENT:

4. CIRCUIT DIAGRAM:

5. EQUIPMENT
• A Light dependent resistor(LDR)
• A NPN transistor- BC547
• A Resistor- 100 K Ohm
• A Resistor-470 Ohm
• Light emitting diode(LED)
• Connecting wires- Use single-core plastic-coated wire
• 9V DC Battery
• Breadboard

6. LDR:
• What is a Light Dependent?
• LDR is a semiconductor device. When light fall on LDR, LDR acts high resistance and
when dark fall on LDR, acts low resistance.

7. LED LIGHT:
• What is the LED light?
• A light-emitting diode (LED) is a semiconductor device. LED have two junction. One
p-junction and another n-junction. P-type connect with positive side of battery and N-
type connect with negative side of battery.

8. NPN TRANSISTOR:
• NPN transistor is a semiconductor device. NPN transistor have three junction. Two n-
type semiconductor and one p-type semiconductor. NPN transistor have three
terminal. Base, collector and emitter.

9. BREADBOARD, BATTERY, WIRE:

10. WORKING PROCESS:
• LDR have two side. One side connect with transistor base terminal and another
side connect with transistor emitter terminal.
• R2 100k resistor connect one side connect base terminal and another side
connect with R1 470Ohm resistor.
• R1 resistor have tow side. One side connect with R2 and battery positive
side. And another side connect with positive side of LED.
• A D1 LED diode one side connect with R2 resistor and another side connect
with transistor collector terminal.
• Transistor base terminal connect with LDR and R2 resistor. Collector
connect with LED negative side. And emitter terminal connect with LDR and
battery negative side.
• Battery positive side connect with R1 resistor. And negative side connect with
transistor emitter terminal.

11. CIRCUIT DIAGRAM:

13. APPLICATION
• Road Light Control.
• Lamp post.
• Home Security Light Control.
• CC Camera (Night Mode).
• Mobile Phone Tower Signal Light.

14. ADVANTAGE
• When electricity is gone light is on and when electricity is come light is
off at home.
• This circuit save time.
• It save Power.
• It help to Smart Life.
• Low maintenance.
• Automatic control.

15. DISADVANTAGE
•Sometime it problem in Cloud Weather.
•Continuously clear dust on the LDR, after few days.

16. • A Light dependent resistor(LDR) ---- 5tk
• A NPN transistor- BC547 ---- 8tk
• A Resistor- 100 K Ohm ----- 1tk
• A Resistor-470 Ohm ---- 1tk
• Light emitting diode(LED) ----- 3tk
• Connecting wire ----- 10tk
• 9V DC Battery ----- 45tk
• Breadboard ----- 25tk
_______________________________________
Total: = 95tk
TOTAL COST OF OUR PROJECT:

17. REFERENCE:
http://www.buildcircuit.com
http://www.edgefxkits.com/
http://www.electroschematics.com/
http://www.electronics-project-design.com/

18. THANK YOU.