Abstract: A current source device controls a rate of change of current flowing through a load so that the change rate of the current is equal to a change rate of a fluctuating supply voltage. A first transistor is fed with the supply voltage via a first resistor connected to its collector and a second resistor connected to its emitter. A second transistor has a base connected to a base of the first transistor, an emitter connected to a third resistor and a collector connected to a load. A current to the load is fed from the supply voltage via the load, the collector and emitter of the second transistor and the third resistor. The collector and base of the first transistor are respectively connected to a base and an emitter of a third transistor having a collector fed with the supply voltage.

Abstract: In an integrated pressure sensor, a silicon chip for pressure detection and a substrate for supporting the silicon chip are made of the same material, the silicon chip has a thin diaphragm portion and a peripheral fixed portion thicker than the diaphragm portion, and the silicon chip is bonded to the substrate through a thin insulating film.

Abstract: A semiconductor strain gauge is arranged as a bridge having four piezoresistive elements which each include a low impurity concentration diffused portion and a heavily-doped diffused portion. The resistance values of the two low impurity concentration diffused portions opposite each other in the bridge are greater than the resistance values of the other two lower impurity concentration portions. The resistances of the heavily-doped diffused portion are selected so that the resistance of the piezoresistive elements are equal. However, by virtue of the fact that the resistance temperature coefficient of the low impurity portions are greater than the resistance temperature coefficients of the high impurity portions, the overall resistance temperature coefficients of the bridge arms will be different. This permits the zero-point voltage of the bridge to always increase with an increase in temperature.