Abstract: A smoke detector having an audible missing primary power source indicator, capable of indicating the absence of a primary power source powering the detector is provided. A missing power source circuit, including a supplementary power source having an effective voltage below a predetermined reference value is connected in parallel with the primary power source of the smoke detector. Additionally, the smoke detector contains low voltage detection and alarm circuitry, connected to the primary and supplementary power sources, to produce an audible warning when the effective voltage powering the smoke detector is determined to be below a predetermined reference value. Primary power to the detector may be supplied by a DC battery, a DC power source which has been converted from AC power or by a combination of the two.

Abstract: A smoke alarm device including self-test reminder circuitry is provided. The smoke alarm includes smoke detection circuitry and a smoke sensor, the functionality of which may be tested using a test switch connected in parallel across the smoke sensor. Additionally, a reminder circuit is provided, the output of which may be used to enable an indicator. The indicator may be the horn or annunciator of the smoke detector, or may be some other type of indicator, such as a light or other audible indicator. Periodically, the reminder circuit will cause the indicator to become enabled so as to remind the consumer to test the smoke alarm. The indicator will remain enabled until the reminder circuit is manually reset by the consumer. Actuation of the test switch simultaneously tests the functionality of the smoke detection circuitry and resets the reminder circuit.

Abstract: An ionization smoke detector is disclosed in which an electric field is established in an ionization chamber which includes an outer cup-shaped electrode defining the chamber and having side wall apertures for permitting airflow therethrough and a circular inner electrode within the chamber. A radiation source is arranged to produce bipolar and unipolar regions in the chamber. A cylindrical control screen coaxial with the outer electrode and spaced therefrom is electrically connected to and supported by the inner electrode in the chamber.

Abstract: A photoelectric smoke detector includes a light source and a light responsive cell and a smoke chamber therebetween all located within a generally cylindrical inner housing which is in turn concentrically located within a generally cylindrical outer housing. The inside surface of the outer housing is reflective, but the inner housing normally prevents light emitted by the light source into the smoke chamber from striking the outer housing. The inner housing contains one or more windows and is rotatable to move the windows to a position wherein light from the source can pass therethrough to the reflective surface of the outer housing and be reflected thereby back to the light responsive cell. The amount of light striking the reflective surface can be continuously adjusted between a normal condition when no light is reflected and a full test condition when a maximum quantity of light is reflected to the light responsive cell.