They use different methods of putting heat into water.
A microwave turns the electricity into RF radiation that is absorbed by the water. To produce that radiation, the input electricity is converted to thousands of volts by a DC power supply. So regardless of whether it’s 120 or 230 input voltage, it all gets converted to the same high voltage DC to run the magnetron.
A classic electric kettle works by running the current from the outlet through a resistive heating element. Double voltage means double heat.
Induction heaters use a power supply to reduce the input voltage while increasing amps and frequency to heat metal through inductance. So, similar to a microwave, the voltage of the outlet is largely irrelevant.
Tl;Dr: microwaves and induction heaters change the supplied voltage to function, so they work the same in UK and US; resistive heaters work faster on 230v like the UK uses.
Wait how does the microwave go faster when it’s also on half the supply voltage?
They use different methods of putting heat into water.
A microwave turns the electricity into RF radiation that is absorbed by the water. To produce that radiation, the input electricity is converted to thousands of volts by a DC power supply. So regardless of whether it’s 120 or 230 input voltage, it all gets converted to the same high voltage DC to run the magnetron.
A classic electric kettle works by running the current from the outlet through a resistive heating element. Double voltage means double heat.
Induction heaters use a power supply to reduce the input voltage while increasing amps and frequency to heat metal through inductance. So, similar to a microwave, the voltage of the outlet is largely irrelevant.
Tl;Dr: microwaves and induction heaters change the supplied voltage to function, so they work the same in UK and US; resistive heaters work faster on 230v like the UK uses.