| 摘要 |
The attenuation circuit detects electrical and magnetic fields, and produces a second field of the same frequency and amplitude which is phase shifted by 180 degrees. Electrical and magnetic components are addressed separately, with the electrical components processed by input and output aerials and an amplifier, and the magnetic components processed by input and output coils. The circuit is intended to attenuate the harmful effects of an electromagnetic field in the vicinity of television and computer screens. This is achieved by producing a second field of the same frequency and amplitude which is phase shifted by 180 degrees. The circuit detects such a field, and has an indicator light (6) to show the strongest region of electromagnetic field. An aerial (1) detects the electric field and the signal is amplified and phase shifted by a circuit (5), prior to application to an output aerial (7). A further amplifier (9) operates the indicator light. A magnetic detection coil (2) is linked by a crossed link (4) to a re-emitting coil (3). Amplification is achieved by increasing the number of turns on the coil (3), by comparison with the detection coil (2).
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