The type of built-in pressure gauge incorporated into the pump/compressor design. Modern pressure gauges differ mainly in the type of scale on which readings are displayed:
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Analogue. A classic pressure gauge equipped with an analogue scale — a round “dial” with an arrow. Such devices are extremely simple and inexpensive, moreover, they are completely autonomous, do not require a power source and can be used in hand and foot devices. However, they are noticeably inferior to digital ones in accuracy: the scale is capable of displaying readings at best with an accuracy of a tenth of an atmosphere, (sometimes up to two tenths or even more), besides, the arrow tends to vibrate when pumped, which makes it difficult to determine the readings. On the other hand, such accuracy in fact is often quite enough, so analogue pressure gauges have been and remain the most popular option.
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Digital. Pressure gauges equipped with an electronic display that shows pressure data. Such devices have high measurement accuracy — often up to hundredths of an atmosphere (or equivalent in other units), besides, they can provide various additional features — for example, hitchhiking (see below) or switching between measurement in atmospheres and and in pounds per inch2. At the same time, digital pressure gauges are much more expensive than analogue ones, the mentioned accuracy is rarely required in fact, and the
...electronics require a power source, which makes it difficult to use in non-electric pumps (batteries would be required, and they have a limited operating time). As a result, this variant has not received much distribution.
— Is absent. There are quite a few pumps and compressors that do not have a pressure gauge at all. On the one hand, this does not allow you to monitor the pressure during the inflation process: you have to control the condition of the tyre “by eye”, and to measure the pressure, disconnect the unit and use a separate pressure gauge. On the other hand, such models turn out to be more compact and inexpensive than similar solutions with pressure gauges, and the described pumping procedure, although associated with unnecessary hassle, is generally not particularly complicated and does not present any particular difficulties even for inexperienced drivers.Function that
automatically stops operation when a sufficient level of tyre pressure is reached. Usually, the pressure at which the auto-stop is triggered can be set at the discretion of the user.
This function greatly simplifies the work with the pump: the risk of overfilling the tyre is reduced to almost zero, while the user does not need to monitor the pumping process, because the pump will stop at the right time. On the other hand, hitchhiking significantly affects the price. It is found only in electric compressors (see "Type").
The presence of
backlight pressure gauge in the design of the device.
This function requires a power supply, so it is found mainly in the corresponding type of device — compressors (see "Type"). Its purpose is generally obvious: thanks to the backlight, you can easily see the readings of the pressure gauge in low light conditions and even in complete darkness. Such an opportunity when working with a compressor is useful — and not only at dusk and at night, but even in the daytime: many garages, boxes and other places where you have to service a car are very sparingly lit, and even during the day the pressure gauge scale may not be visible without additional illumination.
