Simple, low-cost, low-noise, and energy-efficient digital tire gauge

摘要

A digital tire gauge adapted to be electrically connected to a power supply for measuring a pressure of a fluid in a tire includes, a transducing oscillator mounted in a gauge housing for transducing an imposed pressure of said fluid into a signal of a periodic sequence of cycles, and including a pressure sensor having at least one resistor having a resistance thereof which changes with imposed pressure, a capacitor electrically connected to the pressure sensor for forming therewith an oscillating circuit; and a plurality of inverters electrically connected to the capacitor and pressure sensor to provide a gain for the transducing oscillator, an isolating inverter electrically connected to the transducing oscillator, and functioning as a buffer for impedance matching of the transducing oscillator, a processor electrically connected to the buffer for generating a numerical value in response to a signal from said buffer, a display electrically connected to the processor for displaying a digital reading in accordance with the numerical value and a switch electrically connected respectively at both ends thereof to the processor and the power supply.