| 摘要 |
PURPOSE:To avoid thermal adverse effect from a transistor by interposing a coil between a power source wire and the transistor, by connecting the potential of a shield case to the power source wire in the coil connecting side. CONSTITUTION:The potential of a shield case 16 is connected to the power source wire in the side, to which a coil forming resonant load upon the connection to a transistor 2 is connected, among a positive side power source wire P and a negative side power source wire N. Whereupon, the potential of the shield case 16 comes to the potential of a power source wire opposite to the power source wire coming to the standard of impedance but, because a noise preventing condenser 11 is connected between the positive side power source wire P and the negative side power source wire N and impedances of both of them are almost equal, the internally generated heat of the transistor 2 can be prevented from directly transmitting to the shield case while the reduction in noise is achieved.
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