They are peripherals that convert the movement of the hand into instructions understandable by the computer . The most common is the mouse or mouse on desktop computers, and the touchpad and touch screen on portable devices.


The mouse is a small pointing device designed to be guided on a flat surface with the palm of the hand . It is an ergonomic device equipped with several buttons, a motion capture system, a controller and an information transmission system.

Depending on the characteristics of some of these constituent elements, mice can be classified in different ways.

According to your transmission system:

Wireless mice . They use Wi-Fi, radio frequencies, IR or Bluetooth to exchange information with the computer.

Wired mice . They use a USB or PS / 2 port to connect to the tower.

According to its motion capture system:

Mechanical They have a rigid rubber ball at the bottom that moves by activating two internal wheels that function as a sensor when the user moves the mouse over the surface on which it rests. It has poor durability characteristics due to the presence of moving elements, being especially susceptible to jamming due to dirt accumulated in the mechanisms.

Opticians . It achieves an accuracy of 800 dots per inch (dpi or dpi). They are more durable, but require a mouse pad to function properly.

Laser . Evolution of the previous one that provides higher dpi values: up to 2000 dpi. They are preferred by professional video game players and graphic designers.

Trackballs . Similar to the mechanical mouse. The buttons have priority over the movement of the device. The rubber ball migrates to the top of the mouse and its control is assigned to the pollex.

Multi-touch . It is a hybrid between a mouse and a touchpad .

When choosing a mouse ergonomics is important. In this sense, gaming mice usually offer the greatest configuration possibilities: distribution of installed buttons, resistance opposed by the buttons, dimensions of the grip envelope, etc.


It is a touch panel that performs the functions of the mouse on computer equipment such as netbooks and laptops .

Given its analog functions, the touchpad also has buttons to control the computer. Although, the most important part is the touch zone. This detects the position of the finger by calculating the electrical capacity present in the different points of the region. Accuracies of 25 microns are achieved.

Some touchpads have multitouch technology that allows you to use multiple fingers simultaneously to operate the system with greater control. Others allow the pressure used to be quantified.

Touch screen

Some netbooks integrate touch control functions on the screen. Typically this solution is most common in mobile phones, tablets, and consumer electronics.

Touchscreens can be resistive, capacitive, and surface acoustic wave . The former are the cheapest and most accurate, but their brightness is 15% lower and they are thicker. Capacitive ones work like previously documented touchpads . The weaker acoustic wave ones use sound localization.

Output devices

They are all those elements that present useful information for the user . In this article, the only one that we consider strictly necessary is the monitor.


It is a screen that converts the bits of information into visual elements that can be easily interpreted by the user.

There are multiple technologies used in monitors: cathode ray tube (CRT), plasma (PDP), liquid crystal (LCD), organic light emitting diodes (OLED) and lasers.

The specifications that matter to us in these peripherals are:

Screen resolution . Currently it is rare to find screens with a resolution lower than 1280 × 768 pixels (high definition or HD). Some common resolutions available in the market are Full HD, Retina Display, and 4K. Resolution defines the aspect ratio of the image and the dimensions of the screen that can be used without losing perceived definition.

Refresh rate . Also known as the vertical scan or refresh rate, this specification refers to the number of frames that can be displayed on the screen each second. The higher the number, the better the perceived fluency. Common refresh rate values ​​are 60, 120, 144 and 240 Hz.

Size . It is measured in inches on the longest diagonal of the rectangle that forms the screen. Geometry is also relevant, there are new generation screens with a concave design from the user’s perspective that improve immersion by giving a more panoramic sensation; it is an optimal solution for media playback applications.

Response times and latency . It measures the time that passes from when the computer has certain information until it is presented. It is relevant in the competitive video game scene, among others.

Technology dashboard . Configuration of connections, color correction, selectors for parameters, and so on.

Power supply and other elements

For the equipment to function properly, an electrical power source is needed that is capable of providing the required energy . The power supply is integrated into the tower and must be dimensioned considering the voltage demand of the computer components. These sources can be modular and semi-modular, and their nominal voltage is usually between 150 and 2000 watts.

The computer case and special application racks are supporting structures for the processing and storage components . It is questionable if they are part of the main hardware , but we include them here anyway.

Finally, taking into account the same details of the previous paragraph, the inclusion of refrigeration in this section can be justified. The cooling system is the set of elements that maintain the temperature of the computer within acceptable values .

Cooling can be achieved by fans, radiation plates, refrigerant ducts, or a combination of the above. Effective heat dissipation is the most important parameter of these systems, but it is also important to know the useful life, the noise generated and the complexity of the installation.

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