Battery-Powered Magnetron

Video Description

In this video I'll explain how a Magnetron works, collect some current/voltage numbers on a typical household magnetron from a microwave oven, and show how to power one off a 12V battery. Typical DIY magnetron videos only show how to remove the transmitter from the microwave oven and run it with its original circuitry off mains power. Here, I'm basically building a high frequency inverter circuit to run off DC so that the entire device is portable. To do this, I have a ZVS oscillator driving a transformer primary, and the secondary coil is connected to a voltage doubler / rectifier to provide about 3.6 kV DC. There's also a low voltage / high current winding on the transformer to provide power for the Magnetron cathode filament. One of the biggest frustrations of this project was trying to deliver enough current to the Magnetron cathode filament with my ZVS flyback transformer. It took a lot of messing around until i discovered that the filament has some RF chokes in series with it, giving it about 2.8 uH of inductance. At 40 KHz, this inductance resulted in too much impedance for enough current to flow. Fortunately, the fix was as simple as adding about 7 uF of capacitance in series with the filament to cancel out the inductive reactance. With a proper waveguide, the microwaves could theoretically be focused into a relatively narrow beam, due to their small wavelength. However, that's a project in and of itself, which I'm not going to tackle in this video. Output power of the 12V circuit in this video is only around 50-60W, but it can easily be increased by using a larger capacitor value in series with the voltage doubler on the transformer output. Be sure to use metal shielding around yourself and valuable electronics if you do this. Schematic Link: https://drive.google.com/file/d/1MyQgRyLYlGqkrFBLRWcR7STFDM9IlVSg/view?usp=sharing Music Used: Local Forecast - Elevator Kevin MacLeod - Bossa Antigua Kevin MacLeod - Lobby Time Topher Mohr and Alex Elena - Fortaleza