The cavity magnetron used in the first microwave ovens in the 1950s was a significant improvement over the ones used in World War II radar sets. While the basic principles of operation were the same, there were several key differences in terms of design and performance.
Here are some of the key differences between the cavity magnetrons used in the two contexts:
Size and weight: The cavity magnetron used in the 1950s microwave ovens was smaller and lighter compared to the ones used in WW2 radar sets. The WW2 magnetrons were large and bulky, often weighing several kilograms, making them impractical for consumer appliances. The miniaturization of the magnetron was an important development that made it suitable for domestic use.
Power output: The magnetron used in WW2 radar sets typically had high power outputs, typically in the range of a few kilowatts to tens of kilowatts. In contrast, the magnetron used in early microwave ovens had lower power outputs, typically around 500 to 800 watts. This reduction in power output was sufficient for heating food but significantly lower than what was used in radar applications.
Operating frequency: The WW2 magnetrons operated at a frequency range of around 9 to 10 GHz (Gigahertz). In contrast, the magnetrons used in early microwave ovens operated at a frequency of around 2.45 GHz. The lower frequency was chosen because it provided better penetration and heating characteristics for food, allowing for more uniform cooking.
Efficiency: The magnetrons used in microwave ovens were designed to be more efficient in converting electrical energy into microwave radiation. They incorporated improvements in the overall design, such as better electron focusing, cooling, and more precise manufacturing techniques. These improvements led to increased efficiency and reduced power consumption.
Reliability and lifespan: The magnetrons used in microwave ovens were designed for long-term domestic use, requiring high reliability and longevity. They were engineered to withstand continuous operation for extended periods without significant deterioration in performance. In contrast, the magnetrons used in WW2 radar sets were often operated intermittently and had a shorter operational lifespan.
Overall, the cavity magnetron used in the first microwave ovens in the 1950s was a refined and miniaturized version of the ones used in WW2 radar sets. The improvements made it suitable for consumer use, with smaller size, lower power output, better efficiency, and longer lifespan.