Abstract: Method and apparatus for detecting an aerosol, such as smoke, is provided. An electric potential is applied to one of a pair of electrically isolated conductors spaced apart from one another by a gap into which smoke may permeate. No potential is applied to the other conductor to attract charge particles to it. The two conductors define a tapering channel for guiding smoke particles to the gap between the conductors. The potential is high enough to ionize any aerosol particles in the gap. These ionized particles then drift to the second conductor, altering its potential. A high-gain amplifier detects any change in the potential of the second conductor and provides an output to indicate detection of an aerosol.