Pressure Transducers

Pressure transducers are devices that can sense pressure in a given substance or environment and convert the signals into analog outputs. These devices can be used to measure liquids, air and even some types of foods.

Strain gauges are fitted to the pressure transducer diaphragm and connected to a Wheatstone bridge circuit. When a change in pressure is sensed, the diaphragm moves which changes the orientation of the strain gauge and in turn changes the electrical resistance. The change in the resistance is taken as the analog electrical signal and this is directly proportional to the pressure that is applied and sensed. The pressure signals can be read on a gauge. Many types of industries use pressure transducers to monitor pressure and to keep it at the proper levels.

Pressure transducer types are based on the type of electrical output. The standard types of pressure transducers are volt, millivolt and 4-20 mille amperes. Higher voltage ratings mean that the pressure transducer is less prone to being effected by things such as noise, vibrations and shocks. Millivolt output transducers are generally the least expensive. They have a low output level and it is recommended to use a steady power source for these transducers. Voltage output transducers have a higher output and may be used with a power source that isn’t as steady, as long as the source keeps a minimum level. 4-20 mA transducers have the strongest output of the three and are less influenced by surrounding electrical devices. This makes them ideal in cases where the signal has to be transmitted over long distances.

There are also various styles of pressure transducers available such as: flush diaphragm pressure transducers, PC board mountable, general purpose transducers, special purpose transducers, heavy duty or industrial transducers, high stability and accuracy pressure transducers, etc. The transducer and the readout instrument or gauge should be kept as near to each other as possible. If they are in the vicinity of a lot of electrical equipment the readout may not be very accurate.

The type of pressure transducer that is needed depends on what the job consists of as different transducers are made to measure different types of pressure. If you are working in water then you should be using a vented gauge device. This will account for any barometric changes and will help to make sure that your daily readouts are as accurate as can be. When you choose a pressure transducer for a task make sure that the type you use corresponds to what it will be used for.


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