IMPROVEMENTS RELATING TO ELECTRICALLY HEATED WATER BOILING VESSELS

摘要

A thick film heating element having a portion of its resistive track within a defined part of the surface area of the heating element formed of a material having a negative temperature coefficient of resistance (NTCR) and having the main part of the track formed of a material having a positive temperature coefficient of resistance (PTCR), the arrangement being such as to compensate, at least in part, for the effect of different supply voltages upon the operating temperature of said track portion.