Some current plastic containers and food wraps are specifically designed to resist radiation from microwaves. Products may use the term "microwave safe", may carry a microwave symbol (three lines of waves, one above the other) or simply provide instructions for proper microwave use. Any of these is an indication that a product is suitable for microwaving when used in accordance with the directions provided.[71]
A microwave’s wattage tells you how much power it has, and more wattage means your food will cook faster and more evenly. You’ll typically see microwaves between 500 and 1,200 watts. Be aware that microwaves with fewer than 700 watts are generally underpowered and add time to the cooking process. These models are a good option for people limited by a budget, looking to save space, or willing to wait a few extra minutes. If you want a fully functional microwave to cook meat and vegetables, look for models with 1,000 watts or more.
^ Gallawa, J Carlton (1989). "A Brief History of the Microwave Oven". The complete microwave oven service handbook : operation, maintenance, troubleshooting, and repair. Englewood Cliffs, N.J.: Prentice Hall. ISBN 9780131620179. OCLC 18559256. Retrieved 11 October 2017. Chapter link is hosted at the Southwest Museum of Engineering, Communication and Computation; Glendale, Arizona.
The development of the cavity magnetron made possible the production of electromagnetic waves of a small enough wavelength (microwaves). American engineer Percy Spencer is generally credited with inventing the modern microwave oven after World War II from radar technology developed during the war. Named the "Radarange", it was first sold in 1946. Raytheon later licensed its patents for a home-use microwave oven that was first introduced by Tappan in 1955, but these units were still too large and expensive for general home use. Sharp Corporation introduced the first microwave oven with a turntable between 1964 and 1966. The countertop microwave oven was first introduced in 1967 by the Amana Corporation. After Sharp introduced low-cost microwave ovens affordable for residential use in the late 1970s, their use spread into commercial and residential kitchens around the world. In addition to their use in cooking food, microwave ovens are used for heating in many industrial processes.