More specifically, I have an electric induction kettle. From what I understand, it heats the water by sending a high frequency (voltage?) signal around ~24kHz. This high frequency signal causes a rapidly changing magnetic field that induces many eddy currents into the material. The bottom of the pot becomes hot and heats the water through conduction. My question is, how is a high frequency signal created from the 120V AC current in the wall in such a small area (the induction device is roughly the size of a large hand).