We explain what a power supply is, the functions that this device fulfills and the types of power supplies that exist.
What is Power Supply?
The power or supply source (PSU in English) It is the device that is responsible for transforming the alternating current of the commercial power line that is received in homes (220 volts in Argentina) into direct or direct current; which is used by electronic devices such as televisions and computers, supplying the different voltages required by the components, usually including protection against possible inconveniences in the electrical supply, such as overvoltage.
Power supplies can be linear or switching:
- Linear fonts They follow the scheme of transformer (voltage reducer), rectifier (conversion of alternating voltage to full wave), filter (conversion of full wave to continuous wave) and regulation (maintenance of the output voltage in the event of variations in the load).
- Commutative sources These, on the other hand, convert electrical energy through high-frequency switching on power transistors. Linear sources are typically inefficiently regulated compared to switching sources of similar power. The latter are the most used when a compact and low-cost design is required.
See also: Series circuit
Power supply functions
The essential functions of the font are four:
- Transformation There it is possible to reduce the input voltage to the source (220 v or 125 v), which is what is supplied by the electrical network. A coil transformer participates there. The output of this process will generate 5 to 12 volts.
- Rectification Its objective is to ensure that voltage oscillations do not occur over time. This phase attempts to go from alternating current to direct current through a component called a rectifier or Graetz bridge. This allows the voltage to not drop below 0 volts, and to always remain above this figure.
- Filtered In this phase the signal is flattened as much as possible; this is achieved with one or more capacitors, which retain the current and let it pass slowly, thereby achieving the desired effect.
- Stabilization When the continuous and almost completely flat signal is available, all that remains is to stabilize it completely.
Types of power supplies
The Power supplies that power the PCs are located inside the case and are generally AT or ATX type. AT power supplies were used until approximately the Pentium MMX came out, at which point ATX power supplies came into use.
The AT sources have connectors to motherboard (this differentiates them from the ATX) and in addition, the power supply is activated through a switch in which there is a voltage of 220 v, which poses a risk when handling the PC. Technologically they are quite rudimentary and are hardly used anymore. Likewise, there was a problem that having two connectors that had to be connected to the motherboard, confusion and short circuits were frequent.
In the ATX power supplies the power supply circuit is more modern and is always active that is, the source is always supplied with a small voltage to keep it on standby. An additional advantage of ATX power supplies is that they do not have an on/off switch, but rather work with a button connected to the motherboard, this makes connections/disconnections easier. Depending on their power and the type of case, they are classified as desktop AT (150-200 W), mid-tower (200-300), tower (230-250 W), slim (75-100 W), ATX desktop ( 200-250W).
