<；P>；PROBLEM TO BE SOLVED: To provide a power transmission circuit capable of effectively transmitting power. <；P>；SOLUTION: The power transmission circuit transmits the power output from a power amplifier with a constant voltage amplitude, by using a coil link formed by a primary circuit having a primary coil and a secondary circuit having a secondary coil. The primary circuit has the primary coil, a first reactance connected in series to the primary coil, the power amplifier with the constant voltage amplitude, and a second reactance connected in parallel to the power amplifier. The first reactance is designed to be constant in the power at the secondary circuit with respect to a minimal distance and a maximal distance between the primary coil and the secondary coil designed preliminarily. The second reactance is designed to be smaller in the peak value of the power amplifier, when the distance between the coils changes from the minimal distance to the maximal distance to improve the power factor of the power amplifier. <；P>；COPYRIGHT: (C)2011,JPO&INPIT
