HPT-7 uses piezoresistive differential pressure sensor as sensing element. Silicon oil is filled in between die and two diaphragms, when measured differential pressure is added on two diaphragms; the pressure could be transferred onto die through silicon oil. Sensor die connects with amplifier circuit through wires, using semi-conductor’s piezoresistive effect, transforming differential pressure signal into electric signal. The whole product is used for differential pressure measurement of water, chemi-industry, power station and hydrology, etc