As you know, there are different types of keyboards for PC : membrane, mechanical, scissor, butterfly… keyboards for all tastes and in all colors. The ones that are more widespread commercially because they are the cheapest to manufacture are the membrane ones, and in this article we are going to tell you how they work , what are their advantages and disadvantages compared to others, and why they are so cheap.
Undoubtedly, the most important advantage of this type of keyboard is that they are the cheapest, and it is not uncommon to find them for 10 euros or even less, including models from leading manufacturers such as Logitech for example. The secret that they are so cheap is a combination of the materials used to make them, and the simplicity of their mechanisms. Let’s see it.
How membrane keyboards work
Unlike a mechanical keyboard, where each key has its own switch, a membrane keyboard consists of three layers, four if they have lighting. The first layer, the upper one, is precisely a rubber membrane that has protrusions so that, when we press the key, it returns to its place. These protuberances have glued metal contacts, which when pressing the key will lower and make contact with other contacts, closing the electrical circuit and sending the signal to the PC.
These bottom contacts are, as a general rule, in another layer that can be a PCB or another membrane and that contains the electrical circuit. This is why they are so cheap, since you simply have to have a PCB with the contacts, the membrane and the outer plastic casing, in addition to the keys, of course.
The operation is as follows: when a key is pressed, it pushes the protrusion of the membrane and the metal part downwards, making this part come into contact with the PCB, closing the circuit and sending the electrical signal that indicates that it is you have pressed the key.
Advantages and disadvantages
The main disadvantage that membrane keyboards have is their precision . Given that until the key does not come down completely and makes perfect contact with the conductive layer, activation does not occur, sometimes pulsations are made that are not registered, and for this reason they are not one of the preferred keyboards for gaming. Many manufacturers have greatly improved this, however, but still cannot compare to the precision of mechanical keyboards for example.
The second disadvantage they have is touch . Since there is no mechanism as such but a simple rubber membrane to make the key go down and then up, the feel they have is soft and imprecise, even unpleasant for many users. In addition, over time this membrane can give itself or deform, which is why its durability is not too great.
Finally, to highlight as a disadvantage with respect to the other keyboards is that since the switches are located in series on a PCB, it has a very limited bandwidth, which means that they tend to have ghosting (except for high-end models, that there are). This means that there are a maximum number of keys that can be pressed simultaneously before the keyboard “jams”.
As for the advantages, the first we have already said before and is that since they are cheap and easy to manufacture, their price is usually quite low and we can find them even below 10 euros. The second great advantage is the ease of cleaning that they have, as well as their resistance to liquid spills since there are no physical switches.