AC electric fieldmeter

Claim 2

An instrument to measure the intensity of an AC electric field comprising: first and second sensitive electrodes positionable in the electric field at the point at which the electric field intensity is desired to be determined to cause equal and opposite electrical charges to be induced thereon, an operational amplifier having plus and minus inputs and an output, the first sensitive electrode being connected to the minus input and the second sensitive electrode being connected to the plus input, first and second integrating means, the first integrating means being connected between the output of the operational amplifier and the minus input; a circuit common, the second integrating means being connected between the circuit common and the plus input to thereby provide a differential integrator circuit to produce an output voltlage between the output of the operational amplifier and the circuit common, proportional to the differential charge induced on the first and second sensitive electrodes.

Claim 3

An instrument to measure the intensity of an AC electric field as recited in claim 1 further comprising: an electrostatic shield connected to circuit common surrounding the operational amplifier and the first and second integrating means.

Claim 4

An instrument to measure the intensity of an AC electric field as recited in claim 2 further comprising: indicator means connected between the output of the operational amplifier and circuit common to provide an indication of the intensity of the electric field.

Claim 5

An instrument to measure the intensity of an AC electric field as recited in claim 3 further comprising: resistive means respectively connected across the first and second integrating means to bypass any DC electric field components induced on the first and second sensitive electrodes.

Claim 6

An instrument to measure the intensity of an AC electric field as recited in claim 4 wherein the first and second sensitive electrodes comprise plates positioned perpendicular to the electric field under measurement.

Claim 7

An instrument to measure the intensity of an AC electric field as recited in claim 5 further comprising: a casing to house the operational amplifier, first and second integrating means, first and second resistive means and the indicator means, the first and second sensitive electrodes being mounted to the top and bottom respectively of the casing through electrically insulating means.

Claim 8

An instrument to measure the intensity of an AC electric field as recited in claim 6 further comprising: support means connected to opposite sides of the casing, a handle connected to the support means whereby an operator may manually immerse the instrument at the point in the electric field at which the intensity is designed to be measured.

Claim 9

An instrument to measure the intensity of an AC electric field as recited in claim 7 wherein the indicator means are mounted on the face of the casing for reading by the operator.

Claim 10

An instrument to measure the intensity of an AC electric field as recited in claim 1 further comprising a T-network comprising first and second resistors and a capacitor connected to each of the first and second integrating means to bypass any DC electric field components induced on the first and second sensitive electrodes.

Claim 11

An instrument to measure the intensity of an AC electric field with respect to ground comprising a sensitive electrode positionable in the electric field at the point at which the electric field intensity is desired to be determined to cause an electrical charge to be induced thereon, an operational amplifier having plus and minus inputs and an output, the sensitive electrode being connected to the minus input, integrating means connected between the output of the operational amplifier and the minus input; a ground connection, being connected to the plus input to thereby provide an integrator circuit to produce an output voltage between the output of the operational amplifier and ground proportional to the charge induced on the sensitive electrode, a casing to house the operational amplifier and the integrating means, the sensitive electrode being mounted to the casing through electrically insulating means, and support means connected to opposite sides of the casing, a handle connected to the support means whereby an operator may manually immerse the instrument at the point in the electric field at which the intensity is desired to be measured.

Claim 12

An instrument to measure the intensity of an AC electric field with respect to ground comprising a sensitive electrode positionable in the electric field at the point at which the electric field intensity is desired to be determined to cause an electrical charge to be induced thereon, an operational amplifier having plus and minus inputs and an output, the sensitive electrode being connected to the minus input, integrating means connected between the output of the operational amplifier and the minus input; a ground connection, being connected to the plus input to thereby provide an integrator circuit to produce an output voltage between the output of the operational amplifier and ground proportional to the charge induced on the sensitive electrode, a casing to house the operational amplifier and the integrating means, the sensitive electrode being mounted to the casing through electrically insulating means, and support means connected to opposite sides of the casing, a handle connected to the support means whereby an operator may manually immerse the instrument at the point in the electric field at which the intensity is desired to be measured.

Claim 13

An instrument to measure the intensity of an AC electric field as recited in claim 10 wherein the handle is pivotally connected to the support means.

Claim 14

An instrument to measure the intensity of an AC electric field as recited in claim 11 further comprising: indicator means connected between the output of the operational amplifier and ground connection to provide an indication of the intensity of the electric field.

Claim 15

An instrument to measure the intensity of an AC electric field as recited in claim 12 wherein the indicator means are mounted on the face of the casing for reading by the operator.

Claim 16

An instrument to measure the intensity of an AC electric field as recited in claim 13 further comprising: an electrostatic shield connected to the ground connection surrounding the operational amplifier and the integrating means.

Claim 17

An instrument to measure the intensity of an AC electric field as recited in claim 14 wherein the sensitive electrode comprises a plate positioned perpendicularly to the electric field under measurement.

Claim 18

An instrument to measure the intensity of an AC electric field as recited in claim 15 further comprising: resistive means connected across the integrating means to bypass any DC electric field components induced on the sensitive electrode.

Claim 19

An instrument to measure thE intensity of an AC electric field as recited in claim 15 further comprising a T-network comprising first and second resistors and a capacitor connected to the integrating means to bypass any DC electric field components induced on the sensitive electrode.

Claim 20

An instrument to measure the intensity of an AC electric field as recited in claim 3 further comprising: a casing to house the operational amplifier, first and second integrating means and the indicator means, the first and second sensitive electrodes being mounted to the top and bottom respectively of the casing through electrically insulating means.

Claim 21

An instrument to measure the intensity of an AC electric field as recited in claim 18 further comprising: support means connected to opposite sides of the casing, a handle connected to the support means whereby an operator may manually immerse the instrument at the point in the electric field at which the intensity is designed to be measured.

Claim 22

An instrument to measure the intensity of an AC electric field as recited in claim 19 wherein the indicator means are mounted on the face of the casing for reading by the operator.