this post was submitted on 08 Jan 2026
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Btw, why don't things like this, with short usage time but high current requirements, not have a (big) built-in capacitor to "pre-load", to shorten the heating time and put less load on the house circuits?
Edit: added more context to why.
Because the current requirements are constant and not like a photography flash just a short but extreme amount. There's no point in putting a few Watt seconds into a capacitor if the power requirement is 2kW for minutes.
Plus
For AC power, capacitors don't effectively store energy for later, and would change the power factor to make the resistive load reactive which can bring down the efficiency of the power transfer. For AC power a big ol resistive heater is probably as efficient as you can get, which is part of why those kettles are so simple and boil water so fast.
A kettle that stores energy would need to use DC power, converting it from AC and probably have a very large capacitor, more likely a battery.
Let's make it even MORE complicated. Let's make the kettle a heat pump powered by a bank of supercapacitors!
because we unplug ours when we aren't using it, and capacitors discharge when not under current.
You do know that capacitors can hold charge, even while unplugged, don't you?
They can, but they discharge slowly until they reach a base state. An I mistaken?
You are correct. Even supercapacitors discharge but since they hold more energy it takes longer time before you can notice/measure it.