Microwave s Dave Klamer May 8, 2001
What is a “Microwave?”• Part of the RF spectrum
– 1 - 300 GHz• A microwave oven
800-900 MHz50-600MHz
How A Microwave Oven WorksElectricity flows from from the wall, through fuses
and safety mechanism to the controller
How A Microwave Oven WorksWhen the controller says to go, the triac activates, sending
power to the high voltage transformer (About 3000-4000 V)
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
High Voltage Components• Several components needed• The Magnetron is the heart of
the microwave– 2450 MHz
• 2450 MHz happened to be available• RF Leakage
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
CD in Microwave
• RF energy bounces of from CD, makes neat sparks
* This could cause damage to microwave
Lit Matchstick in Microwave
• Plasma of the fire rapidly absorbs the large amount of RF energy
* This may damage your microwave
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
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 wellThe setup At about 20sec
• A laser printer lamp• A Christmas tree ornament works much like
a CD, but in a 3-D Pattern