NipkowDisc Posted November 14, 2014 vacuum tube technology still be with us, a billion units strong worldwide...the microwave oven!at it's heart be something called a cavity magnetron tube.always a low-cost means of producing microwaves and thus cooking our tidbits for us.yes, the cavity magnetron tube...a vacuum tube apparatus.magnet + electron = magnetron. http://www.youtube.com/watch?v=U0FU1M5Ohr8 Quote Share this post Link to post Share on other sites