US Patent 11432589 Electronic vapor provision system

An electronic vapor provision device includes a first electrical resistive heater for vaporizing a precursor material to generate vapor in an airflow for inhalation by a user and a second electrical resistive heater for vaporizing the precursor material and/or heating said airflow. The first electrical resistive heater has a first thermal coefficient of resistance which is less than a second thermal coefficient of resistance of the second electrical resistive heater. The device further includes a control system to monitor for a change in the resistance of at least the second electrical resistive heater. The second electrical resistance heater therefore serves both as a heater and as a temperature monitor.