Nice to know: What is a power button?

Since we already talked about ACPI and the different states of energy a PC can be in, we continue our little series with the power button. How does it work and what alternatives are there?

The power button is, as the name implies, a switch that can be used to switch electrical appliances on and off. In computers, such as our Mini-PCs, the functionality is now limited to switching on. Whereas in the past, at Windows 95 and such, we had to wait a few minutes until the PC shut down and could be switched off, this now happens automatically. Only for hard reset during operation – for example if the PC hangs – it is still needed. Since this can cause software problems, we should only do this in an emergency. Depending on the settings in the software, the Power Button can also be used to put the running PC into hibernation.

What does a power button look like?

Unlike the interfaces, for instance, the appearance of the power button is not specified. It can take various sizes and shapes, depending on how it fits the design or is practical. Often, the power button has an integrated LED that lights up to signal that the PC is running.

How does a power button work technically?

The power button has a cable, which is connected to two pins on the motherboard. By pressing the power button, a circuit is closed on the mainboard. At that moment, the power supply receives the signal to supply the computer with power and thus start up.

What advantages does the power button have?

Actually, the power button is a very practical invention. After all, it offers the great advantage that we can easily turn a PC on, and in emergency also off.

What are the disadvantages of the power button?

The disadvantage of the power button is that we always have to be close to the PC if we want to turn it on. In many industrial applications, however, the computer is permanently installed and is not necessarily freely accessible. Luckily, there are other ways to turn on a PC.

What are alternatives to the Power Button?

One alternative is an external power switch, as it is offered for example for our BOX N2930. Using a cable, the power button can be placed outside, while the PC is installed in a cabinet, stele or the like.

Another option is Wake on LAN, which starts the PC via the network card. In addition, a computer can also be started via the keyboard or mouse and thus via USB (Wake on USB). The only requirement for these possibilities is ACPI.

Another example is the ultra-small single-board computer Raspberry Pi. It does not have a power button, Wake on LAN or anything like that (because it does not have a BIOS) but boots, when it is supplied with power. To turn it off, like all the other PCs, it has to be shut down manually.

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