1. Study of Refrigerator and
Microwave Oven
COURSE: ELECTRONIC SHOP
COURSE INSTRUCTOR: MR. A.H.M SHATIL
STUDENT NAME: BILLAH, MD. MOSTAKIM
STUDENT ID: 12-21491-2

2. Refrigerator
• A device that produces work by moving
heat from high to low temperature.
• Temperature range for perishable food
storage is 3 to 5 °C (37 to 41 °F).

3. History of Refrigerator
• Refrigerators for home and domestic use were invented by Fred W.
Wolf of Fort Wayne in 1913.

4. Basic Concept of Refrigerator
• Pass a colder liquid continuously around
the object that is to be cooled.

5. Components of Refrigerator & Working Principle
• Main components:
• Compressor,
• Condenser,
• Evaporator and
• Throttling device.

6. Throttling Device
• Obstructs the flow of liquid
• Cold liquid is produced with the help
of this device
• Restricts the flow, which causes a
tremendous pressure drop.

7. Evaporator - Heat Absorption Process
• During the heat absorption process, the
refrigerant further evaporates and
transforms into pure vapor.
• Heat exchanger is required to carry the
cold refrigerant over the body.

8. Compressor
• Raises the pressure back to its
initial level.
• Compressing gas, along with
pressure.

9. Condenser
• Heat exchanger
• Fitted outside of the refrigerator

10. Advantages
• Store food for long time and protects the food from microbes.
• Keep the objects cool and thus protects the food from heat and
direct sunlight

11. Disadvantages
• Use large amount of electricity.
• Refrigerator gas causes global warming.

12. Microwave Oven
• Heats and cooks food by exposing
it to electromagnetic radiation in
the microwave spectrum.
• Quick and efficient.

13. History of Microwave Oven
• Percy Spencer invented the first microwave oven after World War II
from radar technology.

14. Working Principle of Microwave Oven
• Magnetron takes electricity from the
power outlet and converts it into high-
powered radio waves.
• Magnetron blasts these waves into the
food compartment.
• Microwaves bounce back and forth off
the reflective metal walls.
• Microwaves travel through food, they
make the molecules inside it vibrate
more quickly.

15. Advantages
• Cooks many foods in about 1/4th of the time necessary on a gas
burner.
• Saves time in heating frozen foods.

16. Disadvantages
• Cannot cook many popular food.

17. Thankyou