Potentiometers are simple devices that have been around for years. These instruments function by having an electrical contact attached to a moving part. This part then makes contact with a restrictive track. They are common in controlling electrical devices. An example is the volume control we see on audio devices such as a radio or speakers.
They have also been one of the most common position sensors used, hence the name. Despite the potentiometer’s popularity, some engineers are not in favour of their use. The main reason why they do not like them now is that they cannot withstand harsh conditions. Pots, as they are otherwise called, fail in three intense situations:
Pots are prone to break down faster in a high-vibration application. Some examples of this are road vehicles, aircraft, and heavy plant. The restrictive track gets worn out in a couple of hours in this condition. This leads to the pot’s poor performance, despite how simple and inexpensive it is.
2. Foreign matter.
Tiny particles that enter the pot also cause their quick demise. These particulates wear down the surface of the conductive track. This happens when they enter the track and the wiper. An example of this particulate matter is desert sand that gets blown in by the wind. Lubricants are another culprit of this problem. They work as insulators that hinder the pot’s operation when applied on the track. They also act as attractants when combined with tiny particles. The combination of both hastens the breaking down of the pot.
3. Extreme environment.
This is also in relation to the previous item. Extreme weather conditions can bring about tiny particles inside the pot. Humid air, for example, when condensed can bind particulates in the track and wiper. This condensed air can settle on the wiper as well and lead to its corrosion.
The fact that pots are also a passive device contributes to their unreliability these days. They do not need a power supply or extra circuitry to perform their basic function. In short, they are simple devices that are not used with complicated electronics or coils.
These reasons, along with the factors that go with them have made engineers seek an alternative. They have suggested non-contact sensors but switching to them is still up for debate. Some examples of these are Hall effect sensors, optical encoders, and capacitive sensors.
There are also other position-sensing technologies to choose from nowadays. Linear, rotary, and tilt sensors are available from reputable manufacturers.
Pots are becoming a thing of the past due to these technological advancements. Not only will these new sensors be sturdier, but they are also created for specific purposes and have unique functions that others do not have.
Spending a bit more on these new sensors should not be a big burden. Pots might be easy to find anywhere and are affordable, but it is better to invest a bit more for components made to last longer.