How Microwaves Work
On this page, I will explain how microwaves work. Understanding how an appliance
works can help do-it-yourselfers repair the appliance more efficiently. You can
use this page in conjunction with my microwave repair guide to help you better
understand how your microwave works, so you can make repairs yourself. By
repairing your microwave yourself, you can save money from expensive repair
bills.
Warning
Microwave repair can be dangerous! You must unplug the microwave before
attempting to repair it because they use very high voltage on certain internal
parts. After the microwave is unplugged you must also discharge the capacitor
before servicing because the high voltage that the microwave operates on is
stored in the capacitor. To manually discharge the capacitor, place an insulted
handle screwdriver between the diode connection of the capacitor and ground. It
should discharge itself but always discharge it manually!
Smart Board
The smart board,
or the main board, is like the brains of the microwave. This is where everything
is controlled. The function of the smart board is to set the time, power level,
control the cooking time and control all of the automatic controls, such as the
popcorn and defrost. Basically, the smart board distributes power throughout the
microwave as needed or desired by the user. Smart Boards can be purchased at AppliancePartsPros.com.
Transformer
When the microwave
enters the cooking mode, the smart board sends power to the transformer. The
transformer transforms 120-volts from your house wiring to around 5000-volts.
This is done because the magnetron tube operates on this high-voltage.
Transformers can be purchased at AppliancePartsPros.com.
Diode
The power that enters
your house flows one way for 1/60 of a second and then the other way for 1/60 of
a second. The magnetron tube of a microwave uses a direct current that only
flows one way. The diode is a device that only allows the current to flow
one-way converting alternating current to direct current. Diodes can be
purchased at AppliancePartsPros.com.
Capacitor
A capacitor is a
device that stores electricity much like a battery but can be charged and
discharged instantly. As stated above, the power that enters your house flows
one way for 1/60 of a second and then the other way for 1/60 of a second and the
diode only allows the current to flow one way. This means the current will only
flow half of the time. During the time that current is flowing, the magnetron
tube will receive power from this current flow while at the same time charging
the capacitor. Once the current flow stops, the magnetron tube will receive
power from the capacitor. Basically, the capacitor provides a more steady power
flow. Capacitors can be purchased at AppliancePartsPros.com.
Magnetron Tube
The magnetron is at the heart of how microwaves work, they
are what causes the heat to cook your food. The magnetron
tube produces radio waves that excite the water and fat molecules inside the
food causing friction. The friction will cause the food to heat up almost like
rubbing your hands together really fast.This is the most fundamental part of how
microwaves work. Magnetron tubes can be purchased at AppliancePartsPros.com.
Door switches
The door switches
will stop this process the instant the door is opened. Most microwaves have
three door switches so that if one fails there are still two more to ensure that
the cooking stops immediately once the door is opened. Door switches can be
purchased at AppliancePartsPros.com.
Power level
The power level determines what percentage
of time during the cooking cycle that the magnetron tube will be energized. For
example, on power level 10, the magnetron tube will be energized 100% of the
cooking cycle but when the power level is set to 5, the magnetron tube will only
be energized for 50% of the cooking cycle. In normal time cook the power level
will automatically be set to 10 but can be changed manually. In defrost the
power level will be set somewhere around 3. The smart board controls all this.
To sum it all up, the smart board sends voltage to the transformer. The
transformer steps-up the voltage to a much higher voltage. Then the diode
converts alternating current to direct current. The capacitor provides a more
steady current flow. Finally, the magnetron tube produces radio waves to cook
the food. I hope this page helped you better understand how microwaves work so
that you can make repairs to it yourself.
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