I recently used an accelerometer (ADXL335) in my academic project. This sensor has an analog output.
I interfaced this sensor with a microcontroller (PIC18F458) using an ADC module. It was successfully interfaced and showed the correct readings.
Later I noticed in the datasheet of the controller that "the maximum recommended impedance for analog sources is 2.5 kΩ" and the datasheet of the ADXL335 shows that its output impedance is 32 kΩ. I have not used any signal conditioning circuit between the sensor and the controller.
I wonder why I am getting the correct output, even though the source impedance requirement for the ADC module of the controller is not satisfied.