A vaporizer 100 including a reservoir 102 for storing an anesthetic liquid agent and a vaporizing element configured to vaporize the anesthetic liquid agent. A level detector 106 is located outside of and adjacent to the exterior of the reservoir. The level detector includes at least one electrical field sensor configured to provide an output voltage signal based upon the capacitance of material within the reservoir proximate the electrical field sensor. The vaporizer includes a display providing a visual indication of the amount of liquid anesthetic agent in the reservoir.
