Adjust the power setting.
I’m surprised almost everyone I’ve shown this to in real life hadn’t known, and goes on to never use it.
This was less of an issue when more microwaves had two knobs rather than buttons only.
But on most of them the power setting just changes the percentage of time the magentrotron is 'on', but while it is on, its full power. So something like 'low for 40s' becomes a game of russian roulette
But on most of them the power setting just changes the percentage of time the magentrotron is 'on', but while it is on, its full power. So something like 'low for 40s' becomes a game of russian roulette