Electrostatic field measuring apparatus

Claim 2

In an electrostatic field measurement apparatus for detecting the intensity of an electric field adjacent a conducting surface, the combination comprising, a sensing electrode spaced from the conducting surface, means for supporting the sensing electrode including first and second insulators and a conductive feedback electrode, said first insulator disposed between the conducting surface and the feedback electrode, said second insulator disposed between the feedback electrode and the sensing electrode, an AC amplifier having an input connection connected to the sensing electrode as well as an output connection and a positive feedback connection, means for cyclically shielding the sensing electrode thereby to produce a fluctuating voltage thereon in the presence of an electric field, the positive feedback connection of the amplifier being connected to the feedback electrode so that said second insulator is included in a positive feedback path for the amplifier thereby to neutralize any tendency toward current leakage on the surface of the insulator from the sensing electrode to the conducting surface.

Claim 3

The combination as claimed in claim 1 in which the sensing electrode is in the form of spaced sectors lying in a common plane and connected in parallel with one another and in which the shielding means is in the form of a rotating fan-shaped element having corresponding sectors closely overlying the sectors which form the sensing electrode.

Claim 4

In an electrostatic field measurement apparatus for detecting the intensity of an electric field adjacent a conducting surface, the combination comprising, a feedback electrode in the form of a disk having open sectors defined by spaced radial spokes, a sensing electrode in the form of sectors spaced within the open sectors in coplanar relation, means for cyclically shielding the sensing electrode for producing an AC voltage thereon in the presence of an electric field, the shielding means being in the form of a flat rotating fan-shaped member having sectors which correspond to the sectors of the sensing electrode, an insulator interposed between the spokes and the sectors of the sensing element for holding the latter in place, and a further insulator interposed between the feedback electrode and the conducting surface for supporting the feedback electrode, an AC amplifier having an input connection connected to the sensing electrode as well as an output connection and a positive feedback connection, the positive feedback connection of the amplifier being connected to the feedback electrode thereby to neutralize any tendency toward current leakage on the surface of the insulators from the sensing electrode to the conducting surface.

Claim 5

In an electrostatic field measurement apparatus for detecting the intensity of an electric field adjacent a conducting surface, the combination comprising, a feedback electrode in the form of a disk having open sectors defined by spaced radial spokes, a sensing electrode in the form of sectors spaced within the open sectors in coplanar relation, means for cyclically shielding the sensing electrode for producing an AC voltage thereon in the presence of an electric field, the shielding means being in the form of a flat rotating fan-shaped member having sectors which correspond to the sectors of the sensing electrode, an insulator interposed between the spokes and the sectors of the sensing element for holding the latter in place, and a further insulator interposed between the feedback electrode and the conducting surface for supporting the feedback electrode, an AC amplifier having an input connection connected to the sensing electrode as well as an output connection and a positive feedback connection, the positive feedback connection of the amplifier being connected to the feedback electrode thereby to neutralize any tendency toward current leakage on the surface of the insulators from the sensing electrode to the conducting surface.

Claim 6

In an electrostatic field measurement apparatus for detecting the intensity of an electric field adjacent a conducting surface, the combination comprising, a sensing electrode spaced from the conducting surface and in the form of a circular set of similarly shaped electrodes spaced in coplanar relationship and connected in parallel with one another, means for cyclically shielding the sensing electrode for producing an AC voltage thereon in the presence of an electric field, the shielding means being in the form of a rotor having a similar set of shielding electrodes for alternately exposing and shielding the sensing electrode as the rotor rotates, a feedback electrode arranged parallel to the sensing electrode, insulating means interposed between the feedback electrode anD the sensing electrode, and separate insulator means interposed between the feedback electrode and the conducting surface, the shielding means being connected to the conducting surface, an AC amplifier having an input connection connected to the sensing electrode as well as an output connection and a positive feedback connection, the positive feedback connection of the amplifier being connected to the feedback electrode thereby to neutralize any tendency toward current leakage on the surface of the insulators from the sensing electrode to the conducting surface.

Claim 7

In an electrostatic field measurement apparatus for detecting the intensity of an electric field adjacent a conducting surface, the combination comprising, a sensing electrode spaced from the conducting surface and in the form of a circular set of similarly shaped electrodes spaced in coplanar relationship and connected in parallel with one another, means for cyclically shielding the sensing electrode for producing an AC voltage thereon in the presence of an electric field, the shielding means being in the form of a rotor having a similar set of shielding electrodes for alternately exposing and shielding the sensing electrode as the rotor rotates, a feedback electrode arranged parallel to the sensing electrode, insulating means interposed between the feedback electrode anD the sensing electrode, and separate insulator means interposed between the feedback electrode and the conducting surface, the shielding means being connected to the conducting surface, an AC amplifier having an input connection connected to the sensing electrode as well as an output connection and a positive feedback connection, the positive feedback connection of the amplifier being connected to the feedback electrode thereby to neutralize any tendency toward current leakage on the surface of the insulators from the sensing electrode to the conducting surface.

Claim 8

An electrostatic field measuring apparatus employing a plurality of electrostatic detectors mounted upon an aircraft or the like having a conducting surface, each of the detectors capable of sensing the intensity of the electrostatic field with respect to said conducting surface and being of the type including (1) a sensing electrode spaced from the conducting surface, (2) support means interposed between the conducting surface and the sensing electrode including first and second insulating members connected by an intermediate feedback electrode, (3) means for cyclically shielding the sensing electrode for producing a fluctuating voltage thereon in the presence of an electrostatic field, an AC amplifier means having an input connection connected to the sensing electrodes as well as an output connection and positive feedback connections with the positive feedback connections being connected to the feedback electrodes, and means responsive to the amplifier means for indicating the presence of an electrostatic field, individual ones of the detectors being located at different elevations on the aircraft and facing outwardly therefrom in respective directions.

Claim 9

An electrostatic field measuring apparatus employing a plurality of electrostatic detectors mounted upon an aircraft or the like having a conducting surface, each of the detectors capable of sensing the intensity of the electrostatic field with respect to said conducting surface and being of the type including (1) a sensing electrode spaced from the conducting surface, (2) support means interposed between the conducting surface and the sensing electrode including first and second insulating members connected by an intermediate feedback electrode, (3) means for cyclically shielding the sensing electrode for producing a fluctuating voltage thereon in the presence of an electrostatic field, an AC amplifier means having an input connection connected to the sensing electrodes as well as an output connection and positive feedback connections with the positive feedback connections being connected to the feedback electrodes, and means responsive to the amplifier means for indicating the presence of an electrostatic field, individual ones of the detectors being located at different elevations on the aircraft and facing outwardly therefrom in respective directions.

Claim 10

The combination as claimed in claim 5 in which individual ones of the detectors, in addition to being located at different elevations on the aircraft, are located at spaced positions along the length thereof for response of the indicator means to an electrostatic field surrounding the aircraft regardless of the orientation of the aircraft in the field.

Claim 11

The combination as claimed in claim 5 in which the amplifier means is of the type capable of responding to the differential signals from the individual detectors.