1. Microwaves Dave Klamer May 8, 2001

2. What is a “Microwave?” Part of the RF spectrum –1 - 300 GHz A microwave oven 800-900 MHz 50-600MHz

3. Uses of Microwaves Cooking Communication –Radios –Satellites –RADAR Astronomy Medicine

4. How A Microwave Oven Works Electricity flows from from the wall, through fuses and safety mechanism to the controller

5. How A Microwave Oven Works When the controller says to go, the triac activates, sending power to the high voltage transformer (About 3000-4000 V)

6. How A Microwave Oven Works A waveguide guides the microwaves into the cooking chamber The magnetron tube transforms the high voltage into electromagnetic energy A stirring blade spreads the microwaves evenly

7. High Voltage Components Several components needed The Magnetron is the heart of the microwave –2450 MHz 2450 MHz happened to be available RF Leakage

8. Normal Microwave Use RF energy excites water molecules Water molecules rotate on poles, friction with neighbor molecules Friction forces molecules to retain energy, otherwise it would just radiate energy away

9. CD in Microwave RF energy bounces of from CD, makes neat sparks * This could cause damage to microwave

10. Lit Matchstick in Microwave Plasma of the fire rapidly absorbs the large amount of RF energy * This may damage your microwave

11. Tinfoil in Microwave This is why your mom told you to never put tinfoil in the microwave! This kicks out a tremendous amount of heat and noise. Will burn through glass

12. Light Bulbs in Microwave A “burned out” bulb will work fine Gasses in light bulb make it glow different colors when subjected to microwave energy A small neon bulb works really well The setupAt about 20sec A laser printer lamp A Christmas tree ornament works much like a CD, but in a 3-D Pattern