Photoelectric circuit for counting light pulses above a minimium value

Claim 1

AN ELECTRICAL CIRCUIT COMPRISING: A SELECTOR SWITCH HAVING A PLURALITY OF STATIONARY CONTACTS AND A MOVABLE CONTACT FOR MAKING ELECTRICAL CONTACT WITH SAID PLURALITY OF STATIONARY CONTACTS; A PLURALITY OF RESISTORS; CIRCUIT MEANS CONNECTING ONE END OF SAID PLURALITY OF RESISTORS TO VARIOUS ONES OF SAID STATIONARY CONTACTS SO THAT SAID MOVABLE CONTACT OF SELECTOR SWITCH CAN MAKE AN ELECTRICAL CONNECTION WITH SELECTED ONES OF SAID PLURALITY OF RESISTORS; A PHOTOMULTIPLIER DEVICE; CIRCUIT MEANS CONNECTING SAID PHOTOMULTIPLIER DEVICE INTO AN ELECTRICAL CIRCUIT SO THAT SAID PHOTOMULTIPLIER DEVICE GENERATES A PULSE OF ELECTRICAL CURRENT IN RESPONSE TO AN IMPULSE OF LIGHT ENERGY; AN AMPLIFIER CIRCUIT INCLUDING AN INPUT CIRCUIT AND AN OUTPUT CIRCUIT; CIRCUIT MEANS CONNECTING SAID MOVABLE CONTACT OF SAID SELECTOR SWITCH AND THE OTHER END OF SAID PLURALITY OF RESISTORS BETWEEN SAID PHOTOMULTIPLIER DEVICE AND SAID INPUT CIRCUIT OF SAID AMPLIFIER CIRCUIT SO THAT AN AMPLIFIED VOLTAGE PULSE IS DEVELOPED IN SAID OUTPUT CIRCUIT IN RESPONSE TO A PULSE OF ELECTRICAL CURRENT GENERATED BY SAID PHOTOMULTIPLIER DEVICE, SAID AMPLIFIED VOLTAGE PULSE BEING THE FUNCTION OF THE ELECTRICAL CURRENT DEVELOPED BY SAID PHOTOMULTIPLIER DEVICE AND THE VALUE OF RESISTANCE OF SAID RESISTORS AND SELECTED BY SAID SELECTOR SWITCH; A PULSE GENERATING CIRCUIT HAVING AN INPUT VOLTAGE THRESHOLD LEVEL, SAID PULSE GENERATING CIRCUIT BEING ADAPTED TO DEVELOP AN OUTPUT PULSE WHEN SAID THRESHOLD LEVEL IS EXCEEDED; CIRCUIT MEANS CONNECTING SAID AMPLIFIER CIRCUIT OUTPUT CIRCUIT TO SAID PULSE GENERATING CIRCUIT FOR APPLYING SAID AMPLIFIED VOLTAGE PULSE TO SAID PULSE GENERATING CIRCUIT; A MULTIVIBRATOR CIRCUIT HAVING FIRST AND SECOND MODES OF OPERATION AND FIRST AND SECOND INPUT CIRCUITS FOR SWITCHING SAID MULTIVIBRATOR INTO SAID FIRST AND SECOND MODES OF OPERATION RESPECTIVELY, SAID MULTIVIBRATOR CIRCUIT INCLUDING A CHARGING CIRCUIT INCLUDING A SERIES RESISTOR AND CAPACITOR FOR CHARGING SAID CAPACITOR THROUGH SAID SERIES RESISTOR TO A VOLTAGE WHEN IN SAID SECOND MODE OF OPERATION, CIRCUIT MEANS CONNECTED BETWEEN SAID CHARGING CIRCUIT AND SAID FIRST INPUT CIRCUIT FOR SWITCHING SAID MULTIVIBRATOR INTO SAID FIRST MODE OF OPERATION WHEN THE VOLTAGE ACROSS SAID CAPACITOR REACHES A PREDETERMINED LEVEL, AND CIRCUIT MEANS FOR DISCHARGING SAID CAPACITOR WHEN SAID MULTIVIBRATOR IS IN SAID FIRST MODE OF OPERATION; FOURTH CIRCUIT MEANS CONNECTING SAID PULSE GENERATING CIRCUIT TO SAID FIRST INPUT CIRCUIT SO THAT AN OUTPUT PULSE GENERATED BY SAID PULSE GENERATING CIRCUIT SWITCHES SAID MULTIVIBRATOR CIRCUIT IN SAID SECOND MODE OF OPERATION; AND CIRCUIT MEANS CONNECTED TO SAID CHARGING CIRCUIT ADAPTED TO BE CONNECTED TO A MEASURING DEVICE FOR VISUAL DISPLAY OF THE CURRENT FLOW IN SAID CHARGING CIRCUIT WHEN SAID VOLTAGE PULSES DEVELOPED IN SAID AMPLIFIER OUTPUT CIRCUIT EXCEEDS THE THRESHOLD LEVEL OF SAID PULSE GENERATING CIRCUIT.