Tunnel Diode Hydrostatic Pressure Transducer

Abstract

A very sensitive hydrostatic pressure transducer was made using a silicon tunnel diode. The transducer consists, essentially, of a tunnel diode shunted by a resistor which satisfies the stability conditions for operation in the amplifier mode. The advantages of the tunnel diode transducers are (1) small size, (2) sensitivity, and (3) versatility. Since the p‐n junction region is normally 1 mil in diameter or less, miniaturization is possible. Pressure sensitivities as high as 2 mv/v/psi were observed over a 60‐psi pressure range. Expressed in terms of gauge factor, the above sensitivity is equal to about 30 000. Such high sensitivities, within narrow pressure ranges, were achieved at pressures up to 20 000 psi. The pressure range as well as the pressure sensitivity in a chosen pressure interval can be varied very simply by adjusting the values of the shunt resistor and the current through the diode‐resistor combination. Even higher gauge factors can be obtained with other semiconductor materials.