Abstract: A digital readout gauge is disclosed which, for example, may be a tire pressure gauge which is mounted in a small portable housing. A pressure chamber is formed within the housing with a valve core deflator mounted within the housing to depress the core of a standard tire valve and permit the air pressure within the tire to be introduced into the chamber. A wall of the chamber is movable with changes of pressure and a piezoelectric crystal transducer or strain gauge transducer is mounted to be stressed in accordance with movement of this wall to develop an analog voltage in accordance with the air pressure. An electrical circuit is contained within the housing and energizable by a battery carried within the housing. A power switch is actuated to an on condition by movement of the gauge onto the tire valve to energize the electrical circuit with the analog voltage passed to an analog-to-digital converter and then to a digital readout display to display the digital value of the air pressure within the tire.