Microwaves Dave Klamer May 8, 2001

What is a “Microwave?” Part of the RF spectrum – GHz A microwave oven MHz MHz

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

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

How A Microwave Oven Works When the controller says to go, the triac activates, sending power to the high voltage transformer (About 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 well The setupAt about 20sec A laser printer lamp A Christmas tree ornament works much like a CD, but in a 3-D Pattern