Abstract: A smoke alarm for responding to alarm conditions using electrical circuitry having a horn coil placed in series with rectifier circuitry. The series connection of the horn coil with the rectifier circuitry enables suppression of line transients and also eliminates the need for additional transient suppression circuits. An alarm condition causes generation of a short circuit which activates the horn and causes current to pass through the horn; but the high impedance of the horn coil in the rectifier circuit limits the amount of current drawn to low levels for more efficient and safe operation of the smoke alarm. Further, the current flow in the horn will be substantially AC as a result of the series connection of the horn and rectifier circuitry, thereby eliminating the need for an alternate reset current path.

Abstract: A self-contained, portable lighting apparatus is disclosed. The apparatus functions as an escape light in conjunction with smoke detector alarms in that it is activated by detecting the sound of such alarms. A lighting unit includes circuitry for detecting the alarm of a smoke detector, integrating the detected signal over a predetermined time to minimize the incidence of false alarm, circuitry for delaying the shutting off of the light after the alarm signal has ceased and circuitry for detecting a low voltage condition of the batteries and for providing an intermittent sound that is indicative of a low voltage battery condition.