PURPOSE: To obtain a voltage proportional to the change in pressure, by providing another diffused layer in one diffused layer, which has specified concentration and area, on a diaphragm formed with a silicon semiconductor, forming a synthesized resistor body, reducing the change in pressure sensitivity dependent on the change in temperature, and constituting a bridge circuit using four pieces of the semiconductor pressure sensors.
CONSTITUTION: A first impurity layer 2 is formed on a silicon semiconductor 3 by epitaxial growing and the like. A second impurity layer 5 is formed in the first diffused layer by the similar means. Terminals 4 and 4a are formed thereon with a specified interval being provided. An SiO 2 layer 6 is provided on the first and second impurity layers in order to insulate both terminals. The first diffused layer 2 and the second diffused layer 5 are considered to be an assembled body of two kinds of resistors in the longitudinal and lateral directions. A pressure measuring device using these parts includes a Whetstone bridge circuit in order to pickup detected signal as enlarged and accurately as possible. A constant voltage source 14 is connected between input terminals 12 and 13. An output voltage is picked from between output terminals 15 and 16. Thus the temperature dependency of pressure sensitivity can be reduced.