Alarm annunciator with independent acknowledgement indication

Claim 1

AN ELECTRICAL ANNUNCIATOR CIRCUIT COMPRISING IN COMBINATION A D.-C. SUPPLY, A FIRST ELECTRONIC BISTABLE SWITCHING BRANCH CIRCUIT AND A SECOND ELECTRONIC BISTABLE SWITCHING BRANCH CIRCUIT CONNECTED IN PARALLEL CIRCUIT RELATIONSHIP ONE TO THE OTHER ACROSS SAID D.-C. SUPPLY, SAID FIRST ELECTRONIC, BISTABLE SWITCHING CIRCUIT BEING PROVIDED WITH AN ALARM INDICATION LAMP TOGETHER WITH AN ALARM INDICATION CONTROL MEANS CONSISTING OF A SOLID STATE ELECTRONIC BLOCKING MEANS AND A CURRENT-STABLE NEGATIVE RESISTANCE SWITCHING ELEMENT CONNECTED IN SERIES ELECTRICAL CIRCUIT WITH SAID ALARM INDICATION LAMP, SAID ELECTRONIC BLOCKING MEANS HAVING APPLIED THERETO A FIXED PRESELECTED POLARITY BIAS OF MAGNITUDE SUCH THAT THE VOLTAGE DIFFERENCE BETWEEN THE SIDE OF SAID D.-C. SUPPLY HAVING SAID PRESELECTED POLARITY AND SAID BIAS DOES NOT EXCEED THE SWITCHING THRESHOLD OF SAID SWITCHING ELEMENT AND WHEREIN SAID ELECTRONIC BLOCKING MEANS HAS APPLIED TO IT, FIRST, SAID SIGNAL SIGNIFYING THE EXISTANCE OF AN ABNORMAL STATE IN A POINT MONITORED OF SAID PRESELECTED POLARITY AND A VOLTAGE MAGNITUDE DEVELOPING A FIRST VOLTAGE DROP ACROSS SAID SWITCHING ELEMENT EXCEEDING SAID SWITCHING THRESHOLD OF SAID SWITCHING ELEMENT, THEREBY ACTUATING SAID SWITCHING ELEMENT TO ITS "ON" STATE DRAWING ELECTRICAL CURRENT FROM SAID D.-C. SUPPLY THROUGH SAID FIRST ELECTRONIC BISTABLE SWITCHING BRANCH CIRCUIT TO ESTABLISH A DISTINCTIVE ILLUMINATED STATE OF SAID ALARM INDICATION LAMP AND, SECOND, SAID SIGNAL SIGNIFYING THE RESTORATION OF SAID POINT MONITORED TO NORMAL STATE OF POLARITY OPPOSITE FROM SAID PRESELECTED POLARITY AND A VOLTAGE MAGNITUDE REDUCING THE CURRENT FLOW THROUGH SAID SWITCHING ELEMENT BELOW THE HOLDING CURRENT VALUE OF SAID SWITCHING ELEMENT BELOW THE CURRENT FLOW THROUGH ING ELEMENT TO THE "OFF" STAGE HALTING SAID DRAWING OF ELECTRICAL CURRENT THROUGH SAID FIRST ELECTRONIC, BISTABLE SWITCHING BRANCH CIRCUIT, THUS DISESTABLISHING SAID DISTINCTIVE ILLUMINATED STATE OF SAID ALARM INDICATION LAMP, SAID SECOND ELECTRONIC, BISTABLE SWITCHING BRANCH CIRCUIT BEING PROVIDED WITH AN ACKNOWLEDGEMENT VERIFICATION LAMP SWITCHTOGETHER WITH ACKNOWLEDGEMENT VERIFICATION LAMP SWITCHON MEANS ESTABLISHING A DISTINCTIVE ILLUMINATED STATE OF SAID ACKNOWLEDGEMENT VERIFICATION LAMP RESPONSIVE TO THE ESTABLISHMENT OF SAID DISTINCTIVE ILLUMINATED STATE OF SAID ALARM INDICATION LAMP, AND MANUALLY OPERATED MEANS DISESTABLISHING AT WILL SAID DISTINCTIVE ILLUMINATED STATE OF SAID ACKNOWLEDGEMENT VERIFICATION LAMP.