Photomodulator for use with high gain d.c. amplifier

Claim 1

A PHOTOMODULATOR FOR USE WITH A HIGH GAIN D.C. AMPLIFIER COMPRISING TWO SIMILAR CONTROL DEVICES, EACH DEVICE INCLUDING AN ELECTRICALLY CONDUCTIVE TUBE, A PHOTOCONDUCTIVE CELL DISPOSED WITHIN SAID TUBE, SAID CELL HAVING A RESISTANCE UNDER A LIGHT INTENSITY OF TWO FOOT CANDLES IN THE ORDER OF FIFTY MEGOHMS, A NEON BULB HAVING A LIGHT OUTPUT IN THE ORFER OF ONE HUNDRED FOOT CANDLES DISPOSED IN OPTICALLY COUPLED RELATION TO SAID CELL, AND AN ELECTRICALLY CONDUCTIVE FILM OF UNIFORM LIGHT TRANSMITTING CHARACTERISTICS DISPOSED BETWEEN SAID CELL AND SAID BULB AND ELECTRICALLY CONNECTED TO SAID TUBE, SAID BULBS BEING CONNECTED IN PARALLEL IN AN INPUT CIRCUIT INCLUDING MEANS FOR APPLYING AN ALTERNATING VOLTAGE TO SAID BULBS, AN ASYMMETRICALLY CONDUCTIVE DEVICE CONNECTED IN PARALLEL WITH EACH BULB, AND A SERIES RESISTANCE CAPACITANCE CIRCUIT CONNECTED IN SERIES WITH EACH BULB FOR AUGMENTING THE VOLTAGE APPLIED TO EACH BULB AND CONTROLLING THE CONDUCTION ANGLE OF THE CONTROL DEVICE, AND SAID CELLS BEING CONNECTED IN SERIES WITH AN OUTPUT CIRCUIT FOR CONTROLLING THE CHANNELING OF A D.C. SIGNAL TO SAID AMPLIFIER.