Rf hazard detector

Claim 2

A hand-held device for testing for radio frequency voltage levels comprising a metallic casing adapted to be held in the hand of a tester; a conducting probe projecting from said casing and insulated therefrom; a high resistance having one end thereof connected to said metallic probe; a conducting sleeve disposed about and insulated from said resistor, said sleeve being closed off at one end with said closed off end being connected to the other end of resistance whereby said sleeve functions as a distributed capacitance across said resistor; a variable capacitor connected between the closed off end of said sleeve and said casing, said distributed capacitance and said variable capacitor forming aa voltage divider such that whenever said casing is held in the bare hand of a tester and said probe brought in contact with an isolated conducting object that is being irradiated with radio frequency energy, said radio frequency energy flows to ground through said voltage divider and said tester; means disposed within said casing for developing a signal indicative of the magnitude of said radio frequency flow; means for comparing said signal with a predetermined reference voltage; a light source supported by said casing; and means for operating said light source whenever said signal exceeds said reference voltage by a predetermined amount.

Claim 3

In an arrangement as defined in claim 1 wherein said variable capacitor is mounted on said casing such that it can be varied by said tester to track the frequency of the particular radio frequency energy irradiating said object.

Claim 4

In an arrangement as defined in claim 1 wherein said metallic casing has an apex portion and said conducting probe extends from said apex portion.

Claim 5

A hand-held instrument for determining whether an object is at a dangerouSly high induced radio frequency voltage comprising, in combination a metallic casing adapted to be held in the hand of a tester, said casing having a generally rectangular body portion and a frustro-conical nose portion; a di-electric member having a blunted conical shape closing the apex of said frustro-conical nose portion; a metallic contact probe projecting from said di-electric member and supported therefrom; a high impedance means connected between said probe and said casing, said high impedance means comprising a high ohmage resistor, a distributed capacitance existing across said resistor and a manually adjustable capacitor connected in series with said resistor, said distributed capacitance and said adjustable capacitor performing as a capacitance voltage divider whereby whenever said casing is held in the bare hand of said tester and said probe brought into contact with a conducting object that is being irradiated with radio frequency energy, radio frequency energy will flow to ground through said tester and charge said adjustable capacitor to a voltage level determined by the voltage condition of said conducting object; means for detecting the voltage level developed across said capacitor; and means for comparing said voltage level with a preset level and for providing a visual indication whenever said voltage level exceeds said preset level.

Claim 6

A hand-held instrument for determining whether an object is at a dangerouSly high induced radio frequency voltage comprising, in combination a metallic casing adapted to be held in the hand of a tester, said casing having a generally rectangular body portion and a frustro-conical nose portion; a di-electric member having a blunted conical shape closing the apex of said frustro-conical nose portion; a metallic contact probe projecting from said di-electric member and supported therefrom; a high impedance means connected between said probe and said casing, said high impedance means comprising a high ohmage resistor, a distributed capacitance existing across said resistor and a manually adjustable capacitor connected in series with said resistor, said distributed capacitance and said adjustable capacitor performing as a capacitance voltage divider whereby whenever said casing is held in the bare hand of said tester and said probe brought into contact with a conducting object that is being irradiated with radio frequency energy, radio frequency energy will flow to ground through said tester and charge said adjustable capacitor to a voltage level determined by the voltage condition of said conducting object; means for detecting the voltage level developed across said capacitor; and means for comparing said voltage level with a preset level and for providing a visual indication whenever said voltage level exceeds said preset level.