Abstract: An impedance in an electrochemical gas sensor can be measured by connecting at least one pin in an integrated circuit to at least one electrode in an electrochemical gas sensor, using a damping capacitor to connect the at least one pin in the integrated circuit to an electrical ground, applying a voltage to the electrochemical gas sensor to provide a bias voltage to at least one electrode in the electrochemical gas sensor, receiving a current from at least one electrode in the electrochemical gas sensor, determining a measured gas amount from the received current, activating a switch located within the integrated circuit to isolate the damping capacitor from the at least one pin in the integrated circuit, and measuring an impedance of the electrochemical gas sensor using an excitation signal while the at least one damping capacitor is isolated from the at least one electrode in the electrochemical gas sensor.

Abstract: An apparatus comprises a load resistance connectable in series with the electronic sensor to form a series resistance of the load resistance and the internal impedance of the electronic sensor; an excitation circuit configured to apply a predetermined voltage to a circuit element; and a measurement circuit configured to: initiate applying the predetermined voltage to the series resistance and determining the series resistance; initiate applying the predetermined voltage to the load resistance and determining the load resistance; and calculate the internal impedance of the sensor using the determined series resistance and the load resistance, and provide the calculated internal impedance to a user or process.

Abstract: A multiple output, multiple impedance string digital-to-analog converter (DAC) circuit can provide a first output having a first resolution in response to a first digital input signal and a second output having a second resolution in response to a second digital input signal. A main impedance string and a secondary impedance string can be coupled using switching networks to provide a first DAC output. By coupling additional switches to the main impedance string and by sharing the main impedance string, a second DAC output can be realized.