Abstract: The method for testing a passive infrared sensor, the sensor comprising a housing in which an infrared sensor element with two terminal pins and a circuitry connected to the terminal pins of the infrared sensor element are arranged, the method comprises the steps of repeatedly generating and applying individual known electric charges to one of the terminal pins (26, 28) with a predetermined frequency per time unit and measuring the voltage between the two terminal pins (26, 28), and indicating failure of the passive infrared sensor (10) if the voltage differs from a desired voltage by more than a predetermined value.

Abstract: The sensing device for sensing a physical parameter such as radiation, temperature or the like, comprises an analogue sensor element sensitive for the physical parameter to be sensed and outputting an analogue signal and an analogue two-digital converter (ADC) having an MOS input stage for receiving the analogue output signal of the sensor element so as to convert the analogue output signal to a digital output signal.