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EP0141673A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Filtering electrical signals

Assignee: Thorn Lighting Ltd
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Filing: 1984-11-06
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Granted: —
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Expires: 2004-11-06
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Abstract

Abstract @ A ferrite loop 21 encircles the line 11 and neutral 12, but not the earth cable 13 of a mains supply. The loop 21 also encircles a further loop 22 which comprises a capacitor 23. The further loop 22 including its capacitor 23 forms a parallel LC circuit which provides a high impedance to signals at the resonant frequency of the LC circuit in a circuit including the neutral and earth cables. The filter has substantially no effect on signals at mains frequency, since the loop 21 encircles both the line cable 11 and the neutral cable 12. There is also disclosed a filtering system comprising two such filters arranged along the arm of a T-filter system, the stem of the T comprising a series LC circuit to provide a low impedance path for signals at its resonant frequency.

Inventors

  • 👤 Edward Christopher Thomas Crampton

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-24 19:31
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/54; H04B3/56; H04B2203/00; H04B2203/54; H04B2203/5462; H04B2203/5466; H04B2203/5483; H04B2203/5487; H04B2203/5491

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 50 words
An electrical filter for application to electrical cables including a line cable, a neutral cable and an earth cable, the filter comprising a first loop including a capacitor and a second, ferrite, loop encircling said first loop and for encircling the neutral and line cables but not the earth cable.
Claim 2
Dependent Claim 50 words
An electrical filter for application to electrical cables including a line cable, a neutral cable and an earth cable, the filter comprising a first loop including a capacitor and a second, ferrite, loop encircling said first loop and for encircling the neutral and line cables but not the earth cable.
Claim 3
Dependent Claim 46 words
A filter system comprising two filters as claimed in Claim 1 and a series resonant circuit tuned to the frequency of signals which are desired to be excluded, for connection between one of the line and neutral cables and the earth cable between the two filters.
Claim 4
Dependent Claim 21 words
A filter substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings.
Claim 5
Dependent Claim 21 words
A filter substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings.
Claim 6
Dependent Claim 17 words
A filter system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
Claim 7
Dependent Claim 17 words
A filter system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

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