Annunciator system with circuitry producing an output alarm signal for a discontinuous lamp

Claim 1

An annunciator system having a plurality of normally open drop contacts for controlling illumination of normally dark annunciator lamps connecting to a suitable source of power wherein the improvement comprises; a. a current limiting means connected to the annunciator lamps and to the power source for limiting current through the lamps when the drop contacts are open so that the lamps remain dark; b. a bypass sensing circuit connecting to the lamps and responsive to the limited current flowing through the lamps so that an output alarm signal is produced when the lamps would become discontinuous; c. supervising means connected to said bypass sensing circuit and including a normally deenergized supervisory detection indicating device associated with a group of the lamps for manifesting when a lamp of The associated group is inoperable by manifesting an indication when the output alarm signal is produced by a lamp becoming discontinuous; d. said supervising means further including a memory means for storing a signal indicative of the occurrence of the alarm signal produced a discontinuous lamp; and e. a reset means for clearing said memory means of any signal stored therein.