Electronic monitoring system with selective signal inversion

An electronic monitoring system comprising:

• detector means sensitive to an ambient condition for generating on an output lead a binary signal assuming a predetermined value in response to a significant change in said ambient condition, said detector means being provided with a pair of power-input terminals;
• a voltage-generating network provided with an incoming lead, an outgoing lead and a common lead, said outgoing and common leads being respectively connected to said power-input terminals;
• an electronic switch inserted between said incoming and common leads;
• an Exclusive-OR gate having a first input coupled to said output lead and a second input connected to an ancillary lead, said Exclusive-OR gate having an output connected to a control input of said switch;
• resistance means connecting said second outgoing lead to said second input for applying a signal-inverting biasing potential thereto;
• a utilization circuit including a source of electrical energy in series with a load, said utilization circuit having a first supply terminal connected to said incoming lead and further having a second supply terminal;
• switchover means selectively operable for alternatively connecting said second supply terminal to said common lead in a first operating position and to said ancillary lead in a second operating position;
• and
• asymmetrically conductive impedance means joining said common lead to said ancillary lead for enabling said source to energize said detector means by way of said load in both said operating positions while preventing any significant modification of said biasing potential on said second input in said first operating position but causing such modification in said second operating position whereby said Exclusive-OR gate transmits to said control input the logical complement of said binary signal in said first operating position and the uncomplemented binary signal in said second operating position, conduction of said switch under the control of said Exclusive-OR gate intensifying the current supplied by said source to said load in each of said operating positions.