US Patent 11865251 Electronic vaping device having formulation level indicator

The e-vaping device includes a vaporizer assembly, which includes a heating element, a pre-vapor formulation reservoir, a pre-vapor formulation level indicator including a plurality of discrete indicator segments, and at least one processor. The pre-vapor formulation reservoir may be configured to contain a pre-vapor formulation and the at least one processor may be configured to determine a difference between a first duty cycle of power supplied to the heating element and a second duty cycle of power supplied to the heating element; and adjust the indicator based on the determined duty cycle difference.