Abstract: A branch metal terminal has a branch lead terminal portion with a branch wire connected to this terminal portion through a branch female metal terminal. The branch wire is connected to a female-side wire connected to a mold-type electronic part.

Abstract: The invention relates to a gas sensor using a known gas sensitive element which provides an electrical output signal. For example, the sensitive element has a zirconia solid electrolyte sensitive to oxygen. The gas sensitive element is mounted on a ceramic substrate, and the substrate is partly inserted in a tubular housing, and a hermetic and electrically insulating seal column is formed in the housing to tightly hold the substrate. Lead wires protruding from the substrate are connected to external leads within the housing, and the joints are buried in the seal column. According to the invention, the seal column is formed of a glass-ceramic origitated from a glass which is composed of ZnO, B.sub.2 O.sub.3, SiO.sub.2 and MgO and has a crystallizing temperature of 740.degree.-900.degree. C. The glass-ceramic has a linear expansion coefficient smaller than that of the housing by 3.times.10.sup.-6 /.degree.C. at the most. Preferably alumina ceramic is used as the housing material.

Abstract: An air/fuel ratio sensor with a solid electrolyte oxygen pump and oxygen sensor defining a closed space therebetween. At least in the oxygen pump, porous electrodes sandwich an ionic oxygen conductive solid electrolyte. The voltage impressed on the electrodes of the pump is limited to a predetermined level, e.g., 6 V, in order to prevent blackening and cracking.

Abstract: An apparatus for sensing air-fuel ratio of the present invention is capable of measuring an air-fuel ratio of the air-fuel combustion mixture by sensing a partial pressure of oxygen in the exhaust gas. This apparatus forms a gas regulation chamber by arranging oxygen ion conductive solid electrolytes opposite to each other through a gap. In the gas regulation chamber, diffusion of exhaust gas is regulated. Porous electrodes are formed on both sides of the solid electrolytes. One sensor element formed by one of the solid electrolytes is operated as an oxygen concentration cell element, while the other sensor element formed by the other solid electrolyte is operated as an oxygen pump element. Moreover, the sensor elements are heated in order to activate such elements by heaters provided separately. A constant current is supplied to the oxygen concentration cell element in such a direction as pumping the oxygen into the gas regulation chamber.

Abstract: An air-fuel ratio sensor including a box member having a wall made of oxygen ion-conductive electrolyte having a pair of porous electrodes on opposite sides and a diffusion-limiting portion providing communication between the inside and outside of the box member, and an oxygen gas sensing element formed within the box member by injection and firing. The oxygen gas sensing element has a resistance which varies in accordance with the oxygen partial pressure of the atmosphere in which the sensor is immersed.