Overvoltage-undervoltage sensor

Claim 2

A voltage sensitive device for switching a controlled element between de-energized and energized states as the voltage applied to said device passes two different voltage levels, said device comprising two input terminals across which the sensed voltage is applied, a low-level detecting circuit connected across said two input terminals, said low-level detecting circuit having an output terminal and being operable to cause the voltage appearing at said output terminal to be of one value when said applied voltage is below a predetermined low level and to be of a second value when said applied voltage is above said predetermined low level, a high-level detecting circuit connected across said two input terminals, said high-level detecting circuit having an output terminal and being operable to cause the voltage appearing at said latter output terminal to be of one value when said applied voltage is below a predetermined high level and to be of a second value when said applied voltage is above said predetermined high level, and a comparator circuit connected to both of said output terminals and to said controlled element for energizing and de-energizing said controlled element in response to changes in the combination of voltages appearing at said two output terminals, each of said detecting circuits including a three-terminal semiconductor device of the type which with regard to a first two of its terminals has non-conducting and conducting states and which switches from said non-conducting state to said conducting state when the voltage applied across said first two terminals rises relative to the voltage applied to its third terminal to a point at which said voltage across said first two terminals equals said voltage applied to said third terminal times a given proportionality factor, means for applying a proportion of said applied voltage to one of said first two terminals of each of said two semiconductor devices, two dropping resistances, and means connecting the other one of said first two terminals of each of said two semiconductor devices to one of said input terminals through a respective one of said dropping resistances the side of which resistance opposite from said one input terminal constitutes said output terminal of the associated detecting circuit, and means for applying a reference voltage to the third terminal of said semiconductor device of each of said detecting circuits.

Claim 3

A voltage sensitive device as defined in claim 1 further characterized by said comparator circuit including a third three-terminal semiconductor device of the type which with regard to a first two of its terminals has non-conducting and conducting states and which switches from said non-conducting state to said conducting state when the voltage applied across said first two terminals rises relative to the voltage applied to its third terminal to a point at which said voltage across said first two terminals equals said voltage applied to said third terminAl times a given proportionality factor, said third semiconductor device having its third terminal connected to the output terminal of said high-level detecting circuit and means defining a circuit between the output terminal of said low-level detecting circuit and said one input terminal and passing through said first two terminals of said third semiconductor device which circuit is coupled with said controlled element so as to cause said controlled element to assume one of its said states when current passes through said latter circuit as a result of said third semiconductor being in a conducting state and to cause said controlled element to assume the other of its said states when no current flows through said latter circuit as a result of said third semiconductor device being in its non-conducting state.

Claim 4

A voltage sensitive device as defined in claim 2 further characterized by said latter circuit comprising means connecting one of said first two terminals of said third semiconductor device to said output terminal of said low-level detecting circuit and means connecting the other one of said two terminals of said third semiconductor device to said one input terminal through said controlled element.

Claim 5

A voltage sensitive device as defined in claim 2 further characterized by said latter circuit including means connecting one of said first two terminals of said third semiconductor device to the output terminal of said low-level detecting circuit and means connecting the other one of said first two terminals of said third semiconductor device to said one input terminal through a dropping resistance, and an amplification stage responsive to the voltage appearing across said latter dropping resistance for controlling the energization of said controlled element.

Claim 6

A voltage sensitive device as defined in claim 1 further characterized by said semiconductor devices of said two detecting circuits being programmable unijunction transistors.

Claim 7

A voltage sensitive device as defined in claim 2 further characterized by said two semiconductor devices of said two detecting circuits and said third semiconductor device of said comparator circuit all being programmable unijunction transistors.

Claim 8

A voltage sensitive device for switching a controlled element between de-energized and energized states as the voltage applied to said device passes two different voltage levels, said device comprising two input terminals across which the sensed voltage is applied, a low-level detecting circuit connected across said two input terminals, said low-level detecting circuit having an output terminal and being operable to cause the voltage appearing at said output terminal to be of one value when said applied voltage is below a predetermined low level and to be of a second value when said applied voltage is above said predetermined low level, a high-level detecting circuit connected across said two input terminals, said high-level detecting circuit having an output terminal and being operable to cause the voltage appearing at said latter output terminal to be of one value when said applied voltage is below a predetermined high level and to be of a second value when said applied voltage is above said predetermined high level, and a comparator circuit connected to both of said output terminals and to said controlled element for energizing and de-energizing said controlled element in response to changes in the combination of voltages appearing at said two output terminals, each of said detecting circuits including a voltage divider connected across said two input terminals and having an intermediate tap point, each of said detecting circuits further including a three-terminal semiconductor device which with regard to a first two of its terminals has non-conducting and conducting states and which switches from said non-conducting state to said conducting state when the voltage applied across said first two terminals rises relative to the voltage applied to its third terminal to a point at which said voltage across said first two terminals equals said voltage applied to said third terminal times a given proportionality factor, and each of said detecting circuits further including means connecting one of said first two terminals of said semiconductor device to said tap point of the associated voltage divider and means connecting the other one of said first two terminals of said semiconductor device to one of said input terminals through a dropping resistance the side of which resistance opposite from said one input terminal constitutes said output terminal for said detecting circuit, and means for applying a reference voltage to the third terminal of said semiconductor device of each of said detecting circuits.

Claim 9

A voltage sensitive device for switching a controlled element between de-energized and energized states as the voltage applied to said device passes two different voltage levels, said device comprising two input terminals across which the sensed voltage is applied, a low-level detecting circuit connected across said two input terminals, said low-level detecting circuit having an output terminal and being operable to cause the voltage appearing at said output terminal to be of one value when said applied voltage is below a predetermined low level and to be of a second value when said applied voltage is above said predetermined low level, a high-level detecting circuit connected across said two input terminals, said high-level detecting circuit having an output terminal and being operable to cause the voltage appearing at said latter output terminal to be of one value when said applied voltage is below a predetermined high level and to be of a second value when said applied voltage is above said predetermined high level, and a comparator circuit connected to both of said output terminals and to said controlled element for energizing and de-energizing said controlled element in response to changes in the combination of voltages appearing at said two output terminals, each of said detecting circuits including a voltage divider connected across said two input terminals and having an intermediate tap point, each of said detecting circuits further including a three-terminal semiconductor device which with regard to a first two of its terminals has non-conducting and conducting states and which switches from said non-conducting state to said conducting state when the voltage applied across said first two terminals rises relative to the voltage applied to its third terminal to a point at which said voltage across said first two terminals equals said voltage applied to said third terminal times a given proportionality factor, and each of said detecting circuits further including means connecting one of said first two terminals of said semiconductor device to said tap point of the associated voltage divider and means connecting the other one of said first two terminals of said semiconductor device to one of said input terminals through a dropping resistance the side of which resistance opposite from said one input terminal constitutes said output terminal for said detecting circuit, and means for applying a reference voltage to the third terminal of said semiconductor device of each of said detecting circuits.

Claim 10

A voltage sensitive device as defined in claim 7 further characterized by said means for applying a reference voltage to one of said two detecting circuits comprising a zener diode connected between said third terminal of said semiconductor device of said one detecting circuit and said one input terminal and a resistance connected between said third terminal of said latter semiconductor device and the other of said input terminals.

Claim 11

A voltage sensitive device as defined in claim 7 further characterized by said two semiconductor devices of said two detecting circuits having their third terminals connected to one another, and said means for applying a reference voltage to the third terminal of the semiconductor device of each of said detecting circuits comprising a zener diode connected between said two third terminals and said one input terminal and a resistance connected between said two third terminals and the other one of said input terminals whereby the same reference voltage is applied to both of said semiconductor devices.

Claim 12

A voltage sensitive device for switching a controlled element between de-energized and energized states as the voltage applied to said device passes two different voltage levels, said device comprising two input terminals across which the sensed voltage is applied, two programmable unijunction transistors, means connected with said two input terminals for applying a first proportion of said applied voltage to the anode of the first one of said two programmable unijunction transistors and for applying a second proportion of said applied voltage to the anode of the second one of said programmable unijunction transistors, said first programmable unijunction transistor having its cathode connected to the more negative one of said input terminals through a first dropping resistance and said second one of said programmable unijunction transistors having its cathode connected to said more negative one of said input terminals through a second dropping resistance, means for applying a reference voltage to the gate of each of said two programmable unijunction transistors, and a comparator circuit connected to the more positive sides of said two dropping resistances and to said controlled element for energizing and de-energizing said controlled element in response to changes in the combination of voltages appearing across said two dropping resistances.

Claim 13

A voltage sensitive device for switching a controlled element between de-energized and energized states as the voltage applied to said device passes two different voltage levels, said device comprising two input terminals across which the sensed voltage is applied, two programmable unijunction transistors, means connected with said two input terminals for applying a first proportion of said applied voltage to the anode of the first one of said two programmable unijunction transistors and for applying a second proportion of said applied voltage to the anode of the second one of said programmable unijunction transistors, said first programmable unijunction transistor having its cathode connected to the more negative one of said input terminals through a first dropping resistance and said second one of said programmable unijunction transistors having its cathode connected to said more negative one of said input terminals through a second dropping resistance, means for applying a reference voltage to the gate of each of said two programmable unijunction transistors, and a comparator circuit connected to the more positive sides of said two dropping resistances and to said controlled element for energizing and de-energizing said controlled element in response to changes in the combination of voltages appearing across said two dropping resistances.

Claim 14

A voltage sensitive device as defined in claim 10 further characterized by said comparator circuit comprising a third programmable unijunction transistor having its anode connected to the positive side of said first dropping resistance, having its gate connected to the positive side of said second dropping resistance, and having its cathode connected to said more negative one of said input terminals through a load circuit coupled with said controlled element.

Claim 15

A voltage sensitive device as defined in claim 11 further characterized by said load circuit including said controlled element connected in series with said cathode of said third programmable unijunction transistor and said more negative one of said input terminals.

Claim 16

A voltage sensitive device as defined in claim 11 further characterized by said load circuit including a third dropping resistance connEcted in series with said cathode of said third programmable unijunction transistor and said more negative one of said input terminals, and an amplification stage connected across said third dropping resistance for controlling the energization of said controlled element in response to the voltage appearing across said third dropping resistance.

Claim 17

A voltage sensitive device as defined in claim 10 further characterized by said means connected with said input terminals for applying a first proportion of said applied voltage to the anode terminal of the first one of said programmable unijunction transistors and for applying a second proportion of said applied voltage to the anode terminal of the second one of said programmable unijunction transistors comprising a first voltage divider connected across said two input terminals and having an intermediate tap point connected to the anode of said first programmable unijunction transistor and a second voltage divider connected across said two input terminals and having an intermediate tap point connected to the anode of said second programmable unijunction transistor.

Claim 18

A voltage sensitive device as defined in claim 14 further characterized by each of said two voltage dividers including one adjustable resistance whereby the proportion of the applied voltage supplied to the anode of the associated programmable unijunction transistor may be varied.

Claim 19

A voltage sensitive device as defined in claim 10 further characterized by said two programmable unijunction transistors having their gates connected to one another and said means for applying a reference voltage to the gate of each of said two programmable unijunction transistors comprising a zener diode connected between said two gates and the more negative one of said input terminals and a resistance connected between said two gates and the other of said input terminals whereby the same reference voltage is applied to both of said gates.

Claim 20

A voltage sensitive device for switching a controlled element between de-energized and energized states as the voltage applied to said device passes two different voltage levels, said device comprising two input terminals across which the sensed voltage is applied, two voltage dividers connected across said two input terminals, two programmable unijunction transistors each having its anode terminal connected to an intermediate tap point of a respective one of said voltage dividers, said first programmable unijunction transistor having its cathode connected to the more negative one of said input terminals through a first dropping resistance and said second one of said programmable unijunction transistors having its cathode connected to said more negative one of said input terminals through a second dropping resistance, said two programmable unijunction transistors having their gates connected directly to one another, a zener diode connected between said two gates and said more negative one of said input terminals and a resistance connected between said two gates and the other one of said input terminals so as to apply a common reference voltage to said two gates, and a third programmable unijunction transistor having its anode connected to the positive side of said first dropping resistance and its gate connected to the positive side of said second dropping resistance and having its cathode connected to said more negative one of said input terminals through a load circuit coupled with said controlled element.

Claim 21

A voltage sensitive device for switching a controlled element between de-energized and energized states as the voltage applied to said device passes two different voltage levels, said device comprising two input terminals across which the sensed voltage is applied, two voltage dividers connected across said two input terminals, two programmable unijunction transistors each having its anode terminal connected to an intermediate tap point of a respective one of said voltage dividers, said first programmable unijunction transistor having its cathode connected to the more negative one of said input terminals through a first dropping resistance and said second one of said programmable unijunction transistors having its cathode connected to said more negative one of said input terminals through a second dropping resistance, said two programmable unijunction transistors having their gates connected directly to one another, a zener diode connected between said two gates and said more negative one of said input terminals and a resistance connected between said two gates and the other one of said input terminals so as to apply a common reference voltage to said two gates, and a third programmable unijunction transistor having its anode connected to the positive side of said first dropping resistance and its gate connected to the positive side of said second dropping resistance and having its cathode connected to said more negative one of said input terminals through a load circuit coupled with said controlled element.