Portable electrostatic field safety monitor
First Claim
1. A portable monitoring system for detecting a radiated electrostatic field and producing an audible warning when the intensity of the detected field exceeds a selected predetermined value, comprisingdetector circuit means for deriving a d.c. signal corresponding to the detected field intensity,comparator means for comparing the d.c. signal with a selected reference level for producing an output signal when the d.c. signal level exceeds said reference level, the comparator means including a differential amplifier having a first input circuit connected to receive said d.c. signal and a second input circuit connected to receive a signal defining said reference level, andaudible alarm means responsive to said output signal for sounding a warning,characterized in this, that the monitoring system further comprises a storage device connected in said second input circuit of the differential amplifier for storing the signal defining said reference level, the storage device being interconnected with the output of the detector circuit means by a manually operable switching circuit, said switching circuit including a delay device and being operable to apply the d.c. signal to the storage device after a predetermined delay thereby to reset the reference level so as to correspond to the detected field intensity at a location selected by the user.
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Abstract
A portable monitoring system for detecting a radiated electrostatic field and producing an audible warning when the detected field exceeds a selected value is characterized by a switching device which can be used to reset the threshold warning level and which is not affected by the hand proximity effect. An alarm is sounded when a signal corresponding to the detected field exceeds a value which is stored. The stored value can be reset by a manually operated switching circuit including a delay device operable to delay the storage of a reference level corresponding to the intensity of the field currently detected.
46 Citations
12 Claims
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1. A portable monitoring system for detecting a radiated electrostatic field and producing an audible warning when the intensity of the detected field exceeds a selected predetermined value, comprising
detector circuit means for deriving a d.c. signal corresponding to the detected field intensity, comparator means for comparing the d.c. signal with a selected reference level for producing an output signal when the d.c. signal level exceeds said reference level, the comparator means including a differential amplifier having a first input circuit connected to receive said d.c. signal and a second input circuit connected to receive a signal defining said reference level, and audible alarm means responsive to said output signal for sounding a warning, characterized in this, that the monitoring system further comprises a storage device connected in said second input circuit of the differential amplifier for storing the signal defining said reference level, the storage device being interconnected with the output of the detector circuit means by a manually operable switching circuit, said switching circuit including a delay device and being operable to apply the d.c. signal to the storage device after a predetermined delay thereby to reset the reference level so as to correspond to the detected field intensity at a location selected by the user.
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6. A portable monitoring system for detecting a radiated electrostatic field in the vicinity of a high voltage conductor energized at power line frequency, and for producing an audible warning when the intensity of the detected field exceeds a selected predetermined value, comprising:
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an antenna sensitive to the electrostatic field, a first energizing circuit, detector circuit means connected in said first energizing circuit to be energized thereby, the detector circuit means being coupled to the antenna for deriving a d.c. signal corresponding to the detected field intensity, comparator means for comparing the d.c. signal with a selected reference level for producing an output signal when the d.c. signal exceeds said reference level, the comparator means including a differential amplifier connected in said first energizing circuit to be energized thereby, the differential amplifier having a first input circuit connected to receive said d.c. signal and a second input circuit connected to receive a signal defining said reference level, a second energizing circuit, audible alarm means connected in said second energizing circuit to be energized thereby, and circuit means interconnecting the audible alarm means with the output of said comparator means whereby to respond to said output signal for sounding a warning, said second input circuit of the differential amplifier including a storage device for storing the signal defining said reference level, the storage device being interconnected with the output of the detector circuit means by a manually operable switching circuit, said switching circuit including a delay device and being operable to apply the d.c. signal to the storage device after a predetermined delay thereby to reset the reference level so as to correspond to the detected field intensity at a location selected by the user. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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Specification