| 摘要 |
PROBLEM TO BE SOLVED: To suppress radiation of radio waves, caused by a noise current in a printed circuit board. SOLUTION: A power supply layer 67 is divided into a plurality of lands A, B, and C, and each of the lands A, B, and C is electrically insulated from one another. A high-dielectric layer 68, made of polyamide exists at the upper surface side of the power supply layer 67, and a conductive layer 69, exists on the upper surface of the high-dielectric layer 68. The divided lands A, B, and C are closely connected with one another by capacitance which is formed by the power supply layer 67, the high-dielectric layer 68, and the conductive layer 69. A capacitor due to the capacitance forms a loop-shaped return path of a noise current. The loop-shaped return path of the noise current is formed, so that a loop area becomes extremely narrow. |
