A relatively compact protective apparatus for a pressure sensor includes a diaphragm, a plate, and a sleeve that couples the sensor to the apparatus the diaphragm, whose perimeter edge is attached to the sleeve between the plate and sleeve, forms a compressible cavity in fluid communication, via an opening in the plate, with another cavity formed between the plate and the coupled sensor. A diameter of the diaphragm is relatively small, so the diaphragm includes an undulating zone for enhanced sensitivity in response to pressure. A configuration of the cavities and the opening allows a contained volume of air to transmit a relatively low pressure, via the diaphragm, to the coupled pressure sensor, yet prevents transmission of relatively high pressures to the pressure sensor. A wall of a system fluid circuit line or a manifold connector may be configured to incorporate the protective apparatus therein.
