Nippon Electric Co., Ltd.

Toshio Takaba

Koichi Saito

Nobuaki Shohata

Toshimasa Kobayashi

Toshiyasu Hishii

Tokuo Takeuchi

For use in a gas sensor, an integrated gas sensitive unit comprises, on a single principal surface, a gas sensitive semiconductor element and a first resistor member connected to the element in series for deriving an electrical signal from the element. Both of the element and the first resistor member may be formed by the thick-film integration technique. A heating wire may be attached to the back surface opposite to the principal surface. A combination of secnd and third resistor members may be electrically connected to the series connection in parallel with the second and the third resistor members brought into electrical contact with the element and the first resistor member, respectively, to form a bridge circuit. The combination may be formed on the principal surface together with the series connection or separated from the series connection. Preferably, the first or the second resistor member has the same temperature dependency as the element when the heating wire is attached to the bridge circuit.

Integrated gas sensitive unit comprising a gas sensitive semiconductor

In a printed wiring board having an outwardly flaring through-hole, a conductive pattern is formed on the inwardly directed surface of the hole so as to reach a principal surface of the board only at that circumferential portion of the hole where the pattern is continuous to a pattern portion, if any, formed on the principal surface. The pattern is formed in the through-hole by positive use of that portion of a photoresist film formed on the principal surface to cover the hole which partly protrudes into the hole.

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Tokyo, Japan

Toshio Takaba