Abstract: A device which will find particular use as a medical catheter for measuring the pressure and rate at which blood flows through the heart and the blood vessels.An integrated circuit chip having at least one field effect transistor thereon, which is sensitive to deformation of the chip is mounted at one end inside the device. An elastic membrane typically made from natural rubber, is mounted in an opening in the side of the device. An unattached core or plunger is positioned between the membrane and the other end of the semiconductor chip, thus when pressure is applied to the membrane, it deforms the chip and provides an electric signal.