Thermal photocontrol switch circuit
First Claim
1. A self-configuring photoelectric control circuit for controlling operation of a load based on ambient light, comprising:
- a photocell responsive to ambient light;
a heating resistor connected to said photocell;
a bimetallic element in proximity to said heating resistor and movable in response to generation of heat from said heating resistor;
a switch connected between an input connected to a source and an output connected to said load, said switch operated by said bimetallic element;
a series resistor connected to said heating resistor; and
a resilient shunt connected across said series resistor to provide a current bypass around said series resistor;
wherein said shunt is maintained in a flexed condition to form said bypass; and
wherein a connection of said shunt across said series resistor is formed of a meltable material such that connection to a high voltage source for a duration of time generates heat sufficient to cause melting of said meltable material thereby permitting relaxation of said resilient shunt to open said bypass.
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Accused Products
Abstract
A self-configuring photoelectric control circuit for controlling operation of a load based on ambient light. The photocontrol circuit comprises a photocell responsive to ambient light, a heating resistor connected to the photocell, a bimetallic element in proximity to the heating resistor and movable in response to generation of heat from the heating resistor. A switch is operated by the bimetallic element and is connected between an input connected to a power source and an output connected to the load. A series resistor is connected to the heating resistor and a shunt is connected across the series resistor to provide a current bypass around the series resistor for operation with a low voltage power source, for instance 120 volts. The shunt is maintained in a flexed condition to form the bypass and a connection of the shunt across the series resistor is formed of a meltable material. When a high voltage source is connected to the input for a duration of time, the heating resistor generates sufficient heat to cause melting of the meltable material thereby permitting relaxation of the resilient shunt opening the bypass.
28 Citations
17 Claims
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1. A self-configuring photoelectric control circuit for controlling operation of a load based on ambient light, comprising:
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a photocell responsive to ambient light; a heating resistor connected to said photocell; a bimetallic element in proximity to said heating resistor and movable in response to generation of heat from said heating resistor; a switch connected between an input connected to a source and an output connected to said load, said switch operated by said bimetallic element; a series resistor connected to said heating resistor; and a resilient shunt connected across said series resistor to provide a current bypass around said series resistor; wherein said shunt is maintained in a flexed condition to form said bypass; and wherein a connection of said shunt across said series resistor is formed of a meltable material such that connection to a high voltage source for a duration of time generates heat sufficient to cause melting of said meltable material thereby permitting relaxation of said resilient shunt to open said bypass. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A circuit having an input and an output and configurable for power sources of more than one voltage, comprising:
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an input for connection to a source; an output for connection to a load; a heating element that dissipates heat responsive to a current flow through the circuit; a series resistor connected to said heating element; and a bypass shunt connected in parallel with said series resistor, said bypass shunt having at least one connection formed of a meltable material, said one connection located in proximity to said heating element so that dissipation of heat by said heating element above a predetermined level sufficient to melt said connection opens said bypass shunt to configure said circuit for another voltage. - View Dependent Claims (8, 9, 10, 11)
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12. A method of self-configuring a photocontrol circuit for use with power sources of more than one voltage, comprising the steps of:
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connecting an input to a power source; connecting an output to a load; providing a heating element in a conductive path between the input and a neutral terminal; operating a switch in a conductive path between said input and said output in response to heat dissipated by said heating element; bypassing a series resistor with a tensioned shunt located in the conductive path between said input and said neutral terminal; melting a connection at an end of said shunt to allow said tensioned shunt to relax thereby preventing the bypassing of said series resistor when said input is connected to a power source of a higher voltage. - View Dependent Claims (13, 14, 15, 16)
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17. A method of manufacturing a dual-range self-configuring photo control circuit that has an input for connection to a power source and an output for connection to a load, a photocell responsive to ambient light, a heating resistor connected to said photocell, a bimetallic element in proximity to said heating resistor and movable in response to generation of heat from said heating resistor from a first position to a second position, a switch connecting between said input and said output, said switch operated by said bimetallic element, and a series resistor connected to said heating resistor, the method comprising the steps of:
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connecting one end of a shunt to a location at one end of the series resistor such that the other end of said shunt is a distance away from the other end of said series resistor; bending said shunt so that said other end is in electrical contact with the other end of series resistor and in proximity to the heating resistor; and making a stable connection between the other end of shunt and the other end of the series resistor by means of a meltable solder so that the shunt forms a bypass across said series resistor so long as the solder does not melt.
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Specification