Photoconductive bistable device

Claim 1

AN ELECTRICAL LOAD CIRCUIT INCLUDING IN SERIES A SUBSTANTIALLY CONSTANT VOLTAGE SOURCE FOR APPLYING A SUBSTANTIALLY CONSTANT VOLTAGE THERETO, AN ELECTRICAL LOAD AND A SYMMETRICAL LIGHT RESPONSIVE CURRENT CONTROLLING DEVICE RESPONSIVE TO THE INTENSITY OF EXTERNAL LIGHT AFFECTING THE SAME FOR SUBSTANTIALLY INSTANTANEOUSLY ENERGIZING THE ELECTRICAL LOAD WHEN THE CURRENT CONTROLLING DEVICE IS SUBJECTED TO AT LEAST A PREDETERMINED HIGH LIGHT INTENSITY VALUE, SAID CURRENT CONTROLLING DEVICE BEING EXPOSED TO LIGHT AND COMPRISING NON-RECTIFYING SEMICONDUCTOR MATERIAL AND ELECTRODES IN NON-RECTIFYING CONTACT THEREWITH FOR ELECTRICALLY CONNECTING THE SAME IN SERIES IN THE ELECTRICAL LOAD CIRCUIT, SAID SEMICONDUCTOR MATERIAL HAVING MEANS PROVIDING A THRESHOLD VOLTAGE VALUE, SAID SEMICONDUCTOR MATERIAL HAVING MEANS PROVIDING A NEGATIVE LIGHT-RESISTANCE COEFFICIENT FOR DECREASING AND INCREASING THE RESISTANCE THEREOF AND FOR LOWERING AND RAISING THE THRESHOLD VOLTAGE VALUE THEREOF AS THE VALUE OF THE LIGHT INTENSITY AFFECTING THE CURRENT CONTROLLING DEVICE INCREASES AND DECREASES RESPECTIVELY, SAID SEMICONDUCTOR MATERIAL HAVING AT LEAST PORTIONS THEREOF BETWEEN THE ELECTRODES IN ONE STATE WHICH IS OF HIGH RESISTANCE AND SUBSTANTIALLY AN INSULATOR FOR BLOCKING THE FLOW OF CURRENT THERETHROUGH SUBSTANTIALLY EQUALLY IN EACH DIRECTION BELOW THE THRESHOLD VOLTAGE VALUE WHICH IS LOWERED AND RAISED UPON INCREASE AND DECREASE IN THE VALUE OF THE LIGHT INTENSITY AFFECTING THE CURRENT CONTROLLING DEVICE, SAID SEMICONDUCTOR MATERIAL HAVING AT LEAST PORTIONS THEREOF BETWEEN THE ELECTRODES IN ANOTHER STATE WHICH IS OF LOW RESISTANCE AND SUBSTANTIALLY A CONDUCTOR FOR CONDUCTING THE FLOW OF CURRENT THERETHROUGH SUBSTANTIALLY EQUALLY IN EACH DIRECTION, SAID AT LEAST PORTIONS OF SAID SEMICONDUCTOR MATERIAL BEING CONTROLLED BY THE SUBSTANTIALLY CONSTANT VOLTAGE APPLIED TO THE ELECTRICAL LOAD CIRCUIT, AND BEING SUBSTANTIALLY INSTANTANEOUSLY CHANGED FROM THEIR BLOCKING STATE TO THEIR CONDUCTING STATE WHEN THE THRESHOLD VOLTAGE VALUE OF THE CURRENT CONTROLLING DEVICE IS LOWERED TO AT LEAST THE SUBSTANTIALLY CONSTANT VALUE OF THE APPLIED VOLTAGE UPON INCREASE OF THE VALUE OF THE LIGHT INTENSITY AFFECTING THE CURRENT CONTROLLING DEVICE TO AT LEAST SAID PREDETERMINED HIGH LIGHT INTENSITY VALUE.