Switch failure monitoring in an electrically heated smoking system

A method of controlling an electric heater in an electrically heated smoking system, comprising:

• providing electrical power to the heater in pulses such that during active periods power is supplied to the heater, and during inactive periods, power is not supplied to the heater;
• charging a capacitor in an RC circuit during the inactive periods and allowing the capacitor to discharge during the active periods;
• and
• monitoring a discharge voltage of the capacitor and stopping further supply of electrical power to the heater if the discharge voltage drops below a threshold voltage level.

An electrically heated smoking system, comprising:

• a power supply;
• an electric heater;
• a first switch connected between the electric heater and electrical ground;
• a second switch connected between the power supply and the electric heater;
• an RC circuit comprising a capacitor and being connected to the power supply, configured such that the capacitor charges when the first switch is open and discharges when the first switch is closed;
• and
• control circuitry connected to the RC circuit and being configured to monitor a discharge voltage of the RC circuit and to open the second switch when the discharge voltage of the RC circuit falls below a threshold voltage value.