I’m trying to understand how the magnetron doesn’t burn out. I am assuming 100% efficiency for microwave absorption?
dlcarrier 27 minutes ago [-]
I don't know what you mean by 100% efficiency.
The magnetron burns out from a high standing wave ratio, which is the ratio of how much energy bounces back into it, to how much its outputting. If you aren't heating anything up, the microwaves bounce back and cause damage.
If you have something in the oven that absorbs the microwaves and gets hot, then you're fine. Liquid water does this, including the water in your food, but ceramics do it too. That is why when you cook frozen foods on a ceramic plate, the plate can heat up faster than your food. Once the food defrosts, it'll have liquid water and begin cooking at full speed. Sometimes the food only defrosts from the plate heating up, so you end up with food cooking from the bottom up, instead of the top down.
eugenekay 4 hours ago [-]
It does, eventually. For this type of project don’t use a microwave that you plan on ever using for food - or anything else - ever again.
SequoiaHope 6 hours ago [-]
Same! First learned of these maybe one year ago. Need a spare microwave for experiments…
jacquesm 3 hours ago [-]
Very impressive, I really liked how low tech it all was (except for buying a high purity Si wafer but I can see why growing a crystal that size wasn't on the agenda). Nice to mention Jeri, that first 'cooking with Jeri' episode probably ranks as the all-time-high for makers in my book.
oliculipolicula 3 hours ago [-]
I'm semithrilled to learn that TEOS is hotseller on eBay.. (BC intrusive thoughts of inhaling glass)
Same reaction to purportedly sub-$30/300degC homemade solar cells (BC lead poisoning)
inclusive of equipment
Perovskite Solar Cell: Build a Working One at Home
Anyway, very cool home project.
The magnetron burns out from a high standing wave ratio, which is the ratio of how much energy bounces back into it, to how much its outputting. If you aren't heating anything up, the microwaves bounce back and cause damage.
If you have something in the oven that absorbs the microwaves and gets hot, then you're fine. Liquid water does this, including the water in your food, but ceramics do it too. That is why when you cook frozen foods on a ceramic plate, the plate can heat up faster than your food. Once the food defrosts, it'll have liquid water and begin cooking at full speed. Sometimes the food only defrosts from the plate heating up, so you end up with food cooking from the bottom up, instead of the top down.
Same reaction to purportedly sub-$30/300degC homemade solar cells (BC lead poisoning) inclusive of equipment
Perovskite Solar Cell: Build a Working One at Home
https://youtu.be/3ghatCS0_HY <-- another PhD
https://pubs.rsc.org/ta/article-abstract/5/37/19972/587815/H...
(Somewhat more expensive, though more edible ingredients)
https://www.semiconductor.diy/guides/microwave-solar-panels/