| 摘要 |
PROBLEM TO BE SOLVED: To reduce Joule heating released from the bent part of a power wiring, so as to restrain an electronic circuit board from rising in temperature. SOLUTION: A metallized paste pattern is printed on the surface of a ceramic insulating board 1, the ceramic insulating board 1 is baked together with the metallized paste pattern into an electronic circuit board 1 with a power wiring 2 which is 1 mΩ/(square).mm or above per unit length in actual resistance and capable of having a heavy current of 1A or above to flow through it. In this case, the power wiring 2 is bent at an angle of 45 deg. to 135 deg., the bent part of the wiring 2 is formed gradually wider toward the inside, and if the maximum width of the bent part of the power wiring 2 of a width (w) is represented by wm1, and the width of the simply bent part of the power wiring 2 when the power wiring 2 is simply bent is represented by wm, a relation between wm1 and wm holds which is represented by a formula, wm1>=1.1×wm.
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