Abstract: The invention provides an electric apparatus having a printed circuit board with an improved heat dissipation capacity, and, in particular, to provide an electric apparatus requiring plural printed circuit boards that has an improved heat dissipation efficiency and can be produced at a low cost. A main printed circuit board 10 and a sub board 17 are composite-molded, and the sub board 17 is formed at an area close to or immediately below a heat-generating electronic component 23 or a heat dissipation plate 23a. Thus, by separating the sub board 17 off the main printed circuit board 10, a hole serving as a ventilating hole is formed in the main printed circuit board 10 at the area close to or immediately below the heat-generating electronic component 23 or the heat dissipation plate 23a.

Abstract: An analog/digital recording and playback device and display device which reduce influences of noise between a digital circuit block and analog circuit block to the lowest possible level are provided. A main substrate constituting an analog circuit block which controls an analog signal received from analog broadcasting and an IP conversion circuit substrate constituting a digital circuit block which controls a digital signal received from digital broadcasting are provided inside a housing of a recording and playback device, the main substrate and IP conversion circuit substrate are arranged in parallel and ends thereof are connected as one piece. A shielded substrate for separating the main substrate from the IP conversion circuit substrate is provided in the neighborhood of a joint where the ends are connected. This suppresses noise interference between the main substrate and IP conversion circuit substrate.

Abstract: The invention provides an electric apparatus having a printed circuit board with an improved heat dissipation capacity, and, in particular, to provide an electric apparatus requiring plural printed circuit boards that has an improved heat dissipation efficiency and can be produced at a low cost. A main printed circuit board 10 and a sub board 17 are composite-molded, and the sub board 17 is formed at an area close to or immediately below a heat-generating electronic component 23 or a heat dissipation plate 23a. Thus, by separating the sub board 17 off the main printed circuit board 10, a hole serving as a ventilating hole is formed in the main printed circuit board 10 at the area close to or immediately below the heat-generating electronic component 23 or the heat dissipation plate 23a.

Abstract: A printed wiring board comprises a board member having a major surface virtually broken down into a first zone and a second zone, and at least one through-hole of a predetermined diameter is open at the first zone of the major surface, wherein an electrically conductive test pattern with a first conductive sub-pattern and a second conductive sub-pattern spaced apart from each other is formed on the second zone of the major surface, a first test hole of the first predetermined diameter being formed in the first conductive sub-pattern in such a manner as to split the first conductive sub-pattern into two disconnected pieces without breakage of the second conductive sub-pattern in so far as the first predetermined diameter is matched with a design specification, thereby easily checking the at least one through-hole by using current to see whether or not the predetermined diameter is correct.