Setra is best known for pioneering the variable capacitance principle, the technological innovation behind capacitance-based pressure transducers. Variable capacitance transducers demonstrate industry-leading accuracy especially in low pressure HVAC and critical care applications with accuracies as high as ±0.25” water column (±0.009 PSI).
But while Setra may be known for variable capacitive transducers, there is another viable pressure sensing technology we use for some industrial and OEM products – strain gauge.
What is a strain gauge sensor?
During the manufacturing process, a mechanism is built upon the backside of the transducer’s sensing diaphragm. Through a sputtering process, a small circuit is created that contains on it a Wheatstone-bridge resistance network. As pressure is applied to the diaphragm and unbalances (or strains) the bridge, its electrical resistance is changed and results in a voltage output.
This is comparable to capacitance transducers, where pressure flexes the diaphragm away or towards an electrode, changing its capacitance and converting it to a voltage or current. So why would one choose a strain gauge sensor over a capacitive one in an industrial application? Or vice versa?
Benefits of Strain Gauge Sensors
- Excellent resistance to shock, vibration, and dynamic pressure changes
- Measurement cell is hermetically sealed and does not require additional sealing materials
- Economical to manufacture
Benefits of Capacitive Sensors
- Better for applications that are susceptible to over-pressurization
- Very good hysteresis, linearity, stability, and repeatability, in addition to static pressure measurement capability
- Excellent accuracy in low pressure ranges – as low as 1 PSI.
Not sure what kind of transducer your project needs? CLICK HERE to get in contact with one of our application engineers today.
