Abstract: This detector comprises a variable radio frequency oscillator (1) producing a first electrical signal, a transmission circuit (3) with a capacitive antenna to which said first signal is applied, a reception circuit (6) forming, with the transmission circuit (3), a selective coupler for picking up a second electrical signal at the frequency of the oscillator, and a circuit (9) for comparing the phases of the first and second electrical signals and producing an output signal in response to a variation of the phase shift between said signals due to the presence in the surroundings of the antenna of a foreign body to be detected.The detector further comprises a feedback circuit (13) driven by the output signal of the comparison circuit (9) and controlling the oscillator (1) in order to make the frequency of the first signal vary in the sense which tends to cancel out said variation of the phase shift.

Abstract: A method and apparatus for electrical transmission, wherein an electric current is applied to the primary winding of a mains transformer the secondary winding of which consists of at least one spiral, and a corresponding electric current is collected at the secondary winding of at least one distribution transformer, the primary winding of which consists of said spiral, while the secondary winding of the distribution transformer is mounted in a removable member.