A smoke detector of the ionization type is provided with a movable test target or probe for intercepting alpha radiation within the measuring chamber when moved to a particular position. As a result of the interception of alpha particles, the electrical resistance of the chamber between a pair of electrodes...http://www.google.es/patents/US4194191?utm_source=gb-gplus-sharePatente US4194191 - Smoke simulating test apparatus for smoke detectors
Smoke simulating test apparatus for smoke detectors
