Radiation sensitive surveillance flame detector with reduced extraneous pickup

Claim 1

A SURVEILLANCE FLAME DETECTOR COMPRISING IN COMBINATION, A SILICON SOLAR CELL RESPONSIVE TO RADIATION FROM THE FLAME TO BE DETECTED, AN ALTERNATING VOLTAGE AMPLIFIER HAVING INPUT TERMINALS AND OUTPUT TERMINALS, A TRANSFORMER HAVING A PRIMARY AND A SECONDARY WINDING, THE PRIMARY WINDING OF SAID TRANSFORMER BEING CONNECTED TO SAID CELL AND THE SECONDARY WINDING BEING CONNECTED TO THE INPUT TERMINALS OF SAID AMPLIFIER, SAID AMPLIFIER INCLUDING A FIRST TRANSISTOR CONNECTED AS AN AMPLIFIER HAVING AN INPUT TERMINAL AND A COMMON TERMINAL CONNECTED TO SAID AMPLIFIER INPUT TERMINALS AND AN OUTPUT TERMINAL, A SECOND TRANSISTOR CONNECTED AS AN EMITTER FOLLOWER HAVING AN INPUT TERMINAL, AN OUTPUT TERMINAL AND A COMMON TERMINAL, MEANS CONNECTING THE OUTPUT TERMINAL AND COMMON TERMINAL OF SAID FIRST TRANSISTOR TO THE INPUT TERMINAL AND COMMON TERMINAL OF SAID EMITTER FOLLOWER, AND MEANS CONNECTING THE EMITTER TERMINAL OF SAID EMITTER FOLLOWER TO THE INPUT TERMINAL OF SAID FIRST TRANSISTOR, TO THEREBY PROVIDE NEGATIVE FEEDBACK AROUND SAID FIRST TRANSISTOR AND REDUCE ITS INPUT IMPEDANCE, AN ACTUATING DEVICE AND MEANS CONNECTING SAID ACTUATING DEVICE TO THE OUTPUT TERMINAL AND COMMON TERMINAL OF SAID EMITTER FOLLOWER, WHEREBY THE SIGNAL FROM SAID CELL ENERGIZES SAID DEVICE.