Rms sensing apparatus

Claim 2

An RMS transducer comprising a pair of input terminals, a first series circuit comprising first paths of first and second devices connected to said input terminals for energization therefrom, a second series circuit comprising first paths of third and fourth devices, each of said first paths being characterized by the fact that the voltage established across said first path is proportional to the log of the current flow through said first path, the magnitude of the proportion and of the base of the log of all of said devices being substantially identical, control means energized by the sum of the magnitudes of said established voltage of said first paths of said first series circuit, said control means being coupled to said second series circuit for regulating the current through said second series circuit as the antilog function of the sum of the magnitudes of said established voltages of said first paths of said first series circuit, and shunting means associated with one of said devices of said second series circuit for shunting around its said first path the alternating component of the current through said second series circuit.

Claim 3

The combination of claim 1 in which said first and second and third devices are solid state devices operating as diodes, said fourth device is a solid state triode, and said control means is connected to said fourth device.

Claim 4

The combination of claim 2 in which said sum of the magnitudes of said logs is an electrical voltage, and in which said devices of said second series circuit are arranged such that any current flow caused by said voltage flows through both of said devices of said second circuit.

Claim 5

The combination of claim 3 in which all of said devices are transistors and in which said shunting means is a capacitor.

Claim 6

The combination of claim 4 in which a source of unidirectional potential is connected to energize said second circuit, and a direct current sensing instrument is connected to respond to the flow of direct current through said second circuit.

Claim 7

The combination of claim 5 in which there is provided a full wave rectifier and a transformer, said transformer being connected to said input terminals through said rectifier.

Claim 8

A transducer providing a unidirectional electrical quantity proportional to the RMS value of a pulsating quantity, said transducer comprising a pair of input terminals for energization by said pulsating quantity, a plurality of current flow devices having a current path therethrough, each of said devices being characterized by the fact that the current flow through its said path establishes a first control quantity which is proportional to the log of the current therethrough, the proportion and the base of the log of all of said devices being substantially identical, means connecting said paths of a first and a second of said devices to provide a first series circuit connected to said input terminals, second means connecting said path of a third and a fourth of said devices to provide a second series circuit, current flow controlling means controlling the current flow through said second series circuit in accordance with the magnitude of a second control quantity supplied thereto, means connecting said current flow controlling means to said first series circuit for energization thereof by the magnitude of the sum of said first quantities of said first and second devices, the magnitude of said second control quantity being proportional to the magnitude of said sum, and means preventing the flow of the alternating current component, of the current in said second series circuit, through said path of one of said deviCes of said second series circuit.

Claim 9

A transducer providing a unidirectional electrical quantity proportional to the RMS value of a pulsating quantity, said transducer comprising a pair of input terminals for energization by said pulsating quantity, a plurality of current flow devices having a current path therethrough, each of said devices being characterized by the fact that the current flow through its said path establishes a first control quantity which is proportional to the log of the current therethrough, the proportion and the base of the log of all of said devices being substantially identical, means connecting said paths of a first and a second of said devices to provide a first series circuit connected to said input terminals, second means connecting said path of a third and a fourth of said devices to provide a second series circuit, current flow controlling means controlling the current flow through said second series circuit in accordance with the magnitude of a second control quantity supplied thereto, means connecting said current flow controlling means to said first series circuit for energization thereof by the magnitude of the sum of said first quantities of said first and second devices, the magnitude of said second control quantity being proportional to the magnitude of said sum, and means preventing the flow of the alternating current component, of the current in said second series circuit, through said path of one of said deviCes of said second series circuit.

Claim 10

The combination of claim 7 in which said pulsating quantity is an alternating quantity, a rectifier means is interposed between said input terminals and said first series circuit, said rectifier means being effective to permit current flow through said first series circuit solely in a first direction, and in which there is provided a source of unidirectional potential for current flow through said second series circuit.

Claim 11

The combination of claim 8 in which said third device is a solid state triode comprising a main path including its said first path and a control path including its said first path, said second series circuit including said main path, said current flow controlling means including said control path.

Claim 12

The combination of claim 9 in which said means which prevents the flow of the alternating component is a capacitor connected in parallel with said current path of said one device.

Claim 13

The combination of claim 10 in which said one device is said third device.

Claim 14

The combination of claim 10 in which said one device is said fourth device.

Claim 15

In combination, first and second and third current conducting devices, each of said devices having a main circuit and characterized by the fact that the voltage developed across said device of its said main circuit is substantially proportional to the log of the current flowing through its said main circuit, a fourth regulated current conducting device having a main circuit and a control circuit which controls the magnitude of the current flowing in said main circuit as a function of the magnitude of a first electrical quantity applied to said control circuit, each said circuit of said fourth device being characterized by the fact that the voltage developed thereacross is substantially proportional to the log of the current flowing therethrough, input means adapted to supply a rectified quantity to said first current conducting device whereby unidirectional current flows through said first device in accordance with the instantaneous magnitude of said sinusoidal quantity, input means adapted to supply a rectified quantity to said second current conducting device whereby current flows through said second device in accordance with the instantaneous magnitude of the said quantity applied thereto, a circuit means connected to said first and second devices and connected to said control circuit of said fourth device, said last named circuit means being effective to energize said control circuit with said first signal at a magnitude which is a function of the sum of the magnitudes of the potentials which appear across said first and second devices, an output circuit comprising the series connection of said main circuits of said third and fourth devices, and means eliminating the alternating current component of the current in said output circuit from one of said main circuits of said output circuit.

Claim 16

In combination, first and second and third current conducting devices, each of said devices having a main circuit and characterized by the fact that the voltage developed across said device of its said main circuit is substantially proportional to the log of the current flowing through its said main circuit, a fourth regulated current conducting device having a main circuit and a control circuit which controls the magnitude of the current flowing in said main circuit as a function of the magnitude of a first electrical quantity applied to said control circuit, each said circuit of said fourth device being characterized by the fact that the voltage developed thereacross is substantially proportional to the log of the current flowing therethrough, input means adapted to supply a rectified quantity to said first current conducting device whereby unidirectional current flows through said first device in accordance with the instantaneous magnitude of said sinusoidal quantity, input means adapted to supply a rectified quantity to said second current conducting device whereby current flows through said second device in accordance with the instantaneous magnitude of the said quantity applied thereto, a circuit means connected to said first and second devices and connected to said control circuit of said fourth device, said last named circuit means being effective to energize said control circuit with said first signal at a magnitude which is a function of the sum of the magnitudes of the potentials which appear across said first and second devices, an output circuit comprising the series connection of said main circuits of said third and fourth devices, and means eliminating the alternating current component of the current in said output circuit from one of said main circuits of said output circuit.

Claim 17

The combination of claim 13 in which said means which eliminates the flow of the alternating current component is a capacitor connected in shunt with said one main circuit.

Claim 18

The combination of claim 14 in which said devices each include a p-n semiconductor junction to provide said voltage developed thereacross.

Claim 19

The combination of claim 15 in which said p-n junction of said fourth device is located in each of its said circuits.

Claim 20

The combination of claim 13 in which each of said devices is a transistor, each said transistor includes a base and a collector and an emitter, said first and said second and third devices each having their said base connected to their said collectors.

Claim 21

The combination of claim 15 in which all of said p-n junctions provide substantially the same log value with respect to the current flow therethrough.

Claim 22

The combination of claim 13 in which there is provided a source of unidirectional potential for said output circuit, said means which eliminates the flow of the alternating current component comprises a resistor capacitor network comprising at least a pair of capacitors and a pair of resistors, said resistors being connected in series and between a selected main circuit of said output circuit and said source of potential, a first of said capacitors being connected between a common connection of said resistors and a first point in said output circuit, a second of said capacitors being connected between the common connection of said resistors and said selected main circuit and said first point.

Claim 23

The combination of claim 19 in which a load device is connected into said output circuit intermediate said resistors and said source of potential, and in which locating means selectively determines the location of said first point in said output circuit.

Claim 24

The combination of claim 20 in which said locating means in a first condition determines the location of said first point to be intermediate said main circuits of said output circuit and in a second condition determines said first point to be intermediate said load device and said source of potential.

Claim 25

A transducer comprising a current transformer having output terminals; a full wave rectifying network having alternating current input terminals connected to said transformer output terminals; said network having direct current output terminals; a network having first and second paths connected between said direct current terminals; said first path including in series circuit and in the order named, a first resistor, the p-n junction of a first device, and a log quantity establishing network comprising the p-n junctions of second and third devices; said second path including in series circuit and in the order named a second and third resistor and a first voltage determining element; said second path further including a second voltage determining element in parallel with said second resistor and said first voltage determining element; a third path connected in shunt circuit with said second voltage determining element and including in series circuit and in the order names a load device, the p-n junction of a fourth device and an anti-log quantity establishing network comprising the p-n junctions of a fifth and a sixth device; means connecting a control electrode of said first device to the common connection between said second and said third resistors; means connecting the control electrode of said fourth device the common connection of said third resistor and said first voltage determining element; and means connecting the control electrode of said fifth device to the common connection of said first device and said p-n junction of said second device.

Claim 26

A transducer comprising a current transformer having output terminals; a full wave rectifying network having alternating current input terminals connected to said transformer output terminals; said network having direct current output terminals; a network having first and second paths connected between said direct current terminals; said first path including in series circuit and in the order named, a first resistor, the p-n junction of a first device, and a log quantity establishing network comprising the p-n junctions of second and third devices; said second path including in series circuit and in the order named a second and third resistor and a first voltage determining element; said second path further including a second voltage determining element in parallel with said second resistor and said first voltage determining element; a third path connected in shunt circuit with said second voltage determining element and including in series circuit and in the order names a load device, the p-n junction of a fourth device and an anti-log quantity establishing network comprising the p-n junctions of a fifth and a sixth device; means connecting a control electrode of said first device to the common connection between said second and said third resistors; means connecting the control electrode of said fourth device the common connection of said third resistor and said first voltage determining element; and means connecting the control electrode of said fifth device to the common connection of said first device and said p-n junction of said second device.

Claim 27

The combination of claim 22 which includes a capacitive network connected in parallel with at least one p-n junction of said third path.

Claim 28

The combination of claim 22 which includes a capacitive network connected in parallel with the p-n junction of said fourth and said fifth devices.

Claim 29

The combination of claim 22 which includes an alternating current conducting network, and means selectively connecting said alternating current network in parallel with the p-n junctions of said fourth and fifth devices and in parallel with said load device.

Claim 30

The combination of claim 24 in which said capacitive network includes fourth and fifth resistors and first and second capacitors, said fourth and fifth resistors being connected in series in said third path intermediate said load device and the p-n junctions of said fourth device, said first capacitor being connected between the common point of said fourth and fifth resistors and a first common point between the p-n junction of said fifth device and the p-n junction of said sixth device, said second capacitor being connected between the common point of one of said fourth and fifth resistors and said first common point.

Claim 31

The combination of claim 26 in which means is provided to disconnect said capacitors from said first common point and to connect said capacitors to a second common point intermediate said load device and said seconD voltage determining element.

Claim 32

The combination of claim 22 in which said devices having the p-n junctions are all transistors, said control electrode of said first and said fourth and said fifth devices being bases of the respective said devices, the bases of said second and said third and said sixth devices being connected to one of said collector and emitter thereof to cause said just-named devices to operate as diodes.