Pressure Transducer
The pressure transducer is a sealed gauge reference, capacitive pressure sensor with on
board signal conditioning. It provides a 0.5 volt output and requires a 5 volt regulated power
supply.
In operation the transducer sensor applies pressure via the deflection of a two piece
ceramic diaphragm with one half being a parallel plate capacitor. Changes in capacitance
influenced by the refrigerant pressure under the ceramic diaphragm are converted to an
analog output by the transducer integral signal electronics.
The pressure transducer's electronics are on a flexible circuit board contained in the upper
section of the transducer and provide linear calibration of the capacitance signal from the
ceramic sensing diaphragm.
Benefits of using the pressure transducer over a normal type pressure switch is that the
transducer is constantly monitoring the pressures and sending signals to the electronic
control module (ECM), unlike the normal type pressure switch that has an upper and lower
cut out points. The ECM will disengage the A/C compressor at low or high refrigerant
pressures and electronic diagnostic equipment can be used to extract system pressure
information making it easier when diagnosing problems