7 Reasons ‌Digital Pressure Gauges Are Better Than Analog Pressure Gauges

An air pressure gauge is an instrument designed to measure the amount of pressure exerted by air or other gases. The air pressure gauge is calibrated to translate the air pressure into a visual signal on a dial or a display, which indicates the air pressure in bars or psi (pound per square inch). These components can be air compressors, car air intakes, tire inflators, etc. The air pressure gauge is a simple piece of equipment that can be installed easily, requires little to no maintenance, and is an easy way to quickly know the air pressure within a system, for example, the tires of your vehicle. The two most common types of pressure gauges are digital and analog gauges.

Analog air pressure gauge features a radially formed tube called a Bourdon tube. When pressurized, the Burdon tube straightens and moves an arm attached to its end. This arm is connected to a sector gear which moves according to the movement of the arm. With the help of small gears attached to the sector gear, a slight change in pressure equates to a greater ‌movement in the indicator needle, showing the pressure reading on the dial. As the pressure decreases, the Burdon tube rests back to its original position, and the needle drops as well.

A digital air pressure gauge features pressure sensors that convert the pressure into electronic signals. The most commonly used pressure sensors are piezoresistive sensors. It comprises a diaphragm equipped with piezoresistive elements that create a change in electrical resistance in response to any change in the applied stress. When the air exerts pressure, the diaphragm deflects, causing a change in the cross-sectional area of the piezoresistive elements. This induces a change in the electrical resistance according to which a corresponding value is displayed on the screen of the gauge. Some digital air pressure gauges use a transducer that converts the pressure value to an electrical signal. The pressure readings are displayed on an LCD screen and they require an additional power source, usually a battery.

Although analog and digital air pressure gauges have the same functions, they are very different in technology. However, there are a few distinctive benefits of digital air pressure gauges over standard analog gauges that make them stand out. Some ‌benefits are listed as follows:

Temperature changes can significantly affect the accuracy of pressure readings displayed by the analog gauges. The mechanical linkages can expand and contract with heating and cooling cycles, leading to inaccurate readings. On the other hand, digital gauges offer accurate readings across a wide range of temperatures. Continuous change in pressure can also cause the mechanical linkages to wear out on an analog gauge. With no moving parts, a digital gauge can last a long time.

Analog gauges are often misread because, in order to get an accurate reading, one has to read the dial face perpendicularly. It is called the parallax effect, where reading the dial from an angle can be wrong and the problem further compounds when analog pressure gauges are used in hard-to-reach locations. This issue does not occur in digital gauges because the numeric values displayed on the screen are easily visible, irrespective of the user's position. This makes readability easy and readings more accurate. Furthermore, the digital pressure gauge features a backlit display, which allows you to take accurate readings in pitch dark situations. Conversely, the ability to take a pressure reading is diminished in low-light situations on an analog gauge.

On analog gauges, the continuous pressure pulsations do not allow you to take steady readings because the needle is rapidly bouncing and fluctuating. A digital gauge shows numeric values and pressure readings in decimals that allow you to take better readings. Some good-quality digital pressure gauges allow you to control the refresh rate from slow to fast, making it easy for the technician to read the values. The accuracy and readability of pressure values on a digital pressure gauge provide more precise results when testing for a small leak.

For an analog pressure gauge to truly deliver accurate readings across a large pressure range, the size of the dial has to be very large. This makes it difficult for the user to access the gauge in space-restricted areas. A large gauge can also make the toolbox crowded and inconvenient for a technician to carry. By comparison, digital gauges are very compact and are easily portable.

Usually, an analog gauge has one set of engineering measurement units, e.g. PSI or Bar or kPa, etc. Due to the flexibility of microprocessors used in digital pressure gauges, there is no such limitation as they allow several engineering units the user can choose from. Sophisticated digital air pressure gauges allow you to choose between units of your choice by a push of a button or by scrolling through the menu.

Typical damages associated with an analog pressure gauge include broken glass, damaged pointers, discoloration of the dial face or the glass, etc. The digital gauge can suffer from punctured displays or damaged buttons, but the quality used in their construction ensures they are safe from hazardous chemicals, drops, and shocks. A digital pressure gauge is less likely to get damaged compared to an analog gauge and is less vulnerable to damage.

If an analog gauge goes out of calibration, the technician has to disassemble it, remove the window, check the dial, adjust the screws and pointers, etc. Given the complications and possibility of errors, even after calibrating the gauge compels the users to purchase a new gauge. However, calibrating a digital pressure gauge is comparably very easy and fast. Some digital gauges can be connected to the computer, and the software takes care of the calibration process. Furthermore, the precision linkages used by analog gauges can move out of position due to shocks, vibrations, etc. while handling them in your repair shop. This makes them prone to go out of calibration, which is unlikely in the case of digital pressure gauges.

With a marginal difference in cost between digital and analog gauges, a digital gauge is a better option for all the reasons listed in this article. A little extra cost up front shouldn't be an issue while purchasing digital pressure gauges because not only are they reliable, they last longer and they do not fail like analog gauges, which will save you repair expenses in the long run. When discussing air pressure gauges for cars, the tire pressure gauge is the first thing that comes to mind. Learn more about tire pressure gauges, their types, and how to check your tire pressures correctly.