Setra’s Model GCT225 Series is ideal for pressure measurement applications that require exceptional insensitivity to environmental extremes. The GCT225 is insensitive to factors such as torque effect on the fitting, temperature transients, and RFI effects generated by other instruments and equipment.

Designed with a low cavity volume of 0.11 in3, the GCT225 can be easily purged. All wetted parts are high quality VAR 316L SS, electropolished to 7 Ra (10 max.) finish, and every sensor is mass spectrometer helium leak tested to 1 x 10-9 ATM.CC/sec.

In a typical Setra configuration, a compact housing contains two closely-spaced, parallel, electrically-isolated metallic surfaces, one of which is essentially a diaphragm capable of slight flexing under applied pressure. The diaphragm is constructed of low-hysteresis material such as 17-4 PH SS or a proprietary compound of fused glass and ceramic (Setraceramâ„¢). These firmly secured surfaces (or plates) are mounted so that a slight mechanical flexing of the assembly, caused by a minute change in applied pressure, alters the gap between them (creating, in effect, a variable capacitor). The resulting change in capacitance is detected by a sensitive linear comparator circuit (employing proprietary, custom-designed ASICs), which amplifies and outputs a proportional, high-level signal.