 # Types of Pressure

It is essential to know some basic elements of physics and their units, along with types to understand various concepts in a better way. Basic concepts such as temperature, pressure, atmosphere, velocity, force, magnitude, density, current, light, sound and many more.

In this article, let us know more about pressure and types of pressure in detail.

## What is Pressure?

Pressure is defined as the force applied at the right angles to the surface of an object per unit area over which that force is distributed. There are specified sensors to measure the different types of pressure.

SI unit of pressure is pascal (Pa) and is denoted by the letter ‘p’. Pressure is a scalar quantity.

It is given by the formula:

P= F/A = mg/A

Where,

p is the pressure

F is the magnitude of the force

A is the surface area in contact

The weight of the atmosphere pushing down on each unit area of the earth’s surface constitutes atmospheric pressure. There are many types of pressure, let us know more about it.

## Types Of Pressure

Pressure is classified into three types, they are:

• Absolute pressure
• Gauge pressure
• Differential pressure
• Sealed pressure or vacuum pressure

### Absolute Pressure

It is the type of pressure which takes vacuum or air-free space as the reference. This type of pressure changes as the location changes since there is a change in the atmospheric pressure differences. By using a device like an absolute pressure sensor, it eliminates the reference to varying atmospheric pressure and relies on a specific pressure range for reference.

### Gauge Pressure

Gauge pressure is the difference between absolute pressure and atmospheric pressure. Gauge pressure is also known as relative pressure. The measured pressure is compared to the standard atmospheric pressure at the sea level. Pressure sensors that are used to measure the gauge pressure feature a vent that lets the device use the atmospheric pressure as its reference point. The measured value can be both positive and negative. The positive values are called overpressure. If the gauge pressure value is negative, it is called underpressure or partial vacuum.

If the measured pressure is higher than the standard atmospheric pressure and is equal to the absolute pressure minus atmospheric pressure.

If the measured pressure is then lower than the standard atmospheric pressure, it is subtracted by the absolute pressure from the atmospheric pressure.

Gauge pressure lets you take the reference of the atmospheric pressure as per the location where it is installed.

### Differential Pressure

Differential pressure is a type of gauge pressure that is the difference between the two pressures. It helps to measure the pressure difference between two different points. Differential pressure is used for flow and level measurement applications. Differential pressure is represented using the suffix “d”.

### Sealed Pressure

The vacuum is a space where the absolute pressure is zero. Perfect vacuum condition is difficult to achieve practically and is only a theoretical value. When the pressure is lower than the atmospheric pressure vacuum is created. Practically, the vacuum will only be partially achieved and is known as the partial vacuum. A high vacuum means that the absolute pressure is very low.

The pressure is measured with reference to a sealed chamber closed with atmospheric pressure. The sealed sensor is used to measure the sealed pressure and is made of a sensing element that is sealed to make it air-tight and avoid further changes in the pressure due to change in atmospheric conditions. Sealed pressure is used to protect pressure transducers from damage.

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