Microwaves control the power output by utilizing a technique called pulse width modulation (PWM) or pulse amplitude modulation (PAM). This technique allows the microwave oven to adjust the average power delivered to the food being heated.
Here's a simplified explanation of how it works:
Power settings: Microwave ovens typically have different power settings (e.g., high, medium, low) to provide flexibility in cooking. These power settings correspond to different percentages of the oven's maximum power output.
Time intervals: When you set a specific power level on a microwave, it divides the cooking time into cycles or intervals.
On and off cycles: During each interval, the microwave oven cycles the power on and off. For example, at 50% power, the microwave might be on for 5 seconds and off for 5 seconds, repeating the cycle until the cooking time is complete.
Pulse width modulation (PWM) or pulse amplitude modulation (PAM): The duration of the "on" time within each cycle is adjusted to achieve the desired power level. A higher power setting would have longer "on" periods, while a lower power setting would have shorter "on" periods.
Average power output: By modulating the "on" and "off" periods, the microwave oven effectively reduces the average power output to achieve the desired power level. The food is heated by the energy provided during the "on" periods, while the "off" periods allow the heat to distribute and prevent overheating.
The control of power output in a microwave is achieved through the coordination of the oven's electronic control system and the power supply to the magnetron, which generates the microwaves. The control system regulates the magnetron's power supply based on the selected power level, achieving the desired cooking or heating intensity.
It's important to note that the specific implementation and control mechanisms may vary between microwave oven models, but the underlying principle of adjusting the power output through modulation remains consistent.