Power supplies utilized by PCs work on a technology known as “switching mode” and consequently they are known as switching mode power supplies (SMPS).

Power supplies utilized by PCs work on a technology known as “switching mode” and consequently they are known as switching mode power supplies (SMPS).

There are two vital power supply designs that is; linear power supplies and switching power supplies. Linear power supplies operate by getting the 127 V or 220 V from the power grid and usually step it down to a much lower value, say 12 V, by means of a transformer. This low power supplies online voltage is still in alternating current (AC).

The next step in this process is rectification, which is accomplished by a set of diodes, converting this AC voltage into pulsating voltage by a voltage converter. Afterwards, filtering occurs, which is done by an electrolytic capacitor, converting the pulsating voltage into more or less direct current (DC).

The capacitor gets this current after it swings back, and forth; thus, voltage regulating is quite necessary and either a zener diode or through a voltage regulator integrated circuit can accomplish it. Consequently the output power supplies online voltage obtained after this step is DC voltage.

Despite the fact that linear power supplies work extremely well for several low power products such as wireless telephones or LED lighting, however, when a substantial amount of energy is required, linear power supplies can be quite large for the task. The magnitude of the transformer and the capacitance of the electrolytic capacitor is usually inversely proportional to the frequency of the input AC voltage. This means, the lesser the AC voltage frequency, the greater the size of these components and vice versa.

Seeing as linear power supplies online still utilize the 60 Hz frequency from the power grid- which is fundamentally an exceptionally low frequency – the transformer and the capacitor are quite large. Thirdly, the higher the power supplies online (current) required by the circuit supplied by the power supply, the larger the transformer will be.

Creating linear power supplies for PCs would be rather daft, as it would be extremely large and heavy. The solution lies in utilizing the high frequency switching method using power adapters. On high frequency switching power supplies online, the input voltage gets its frequency hiked up before proceeding into the transformer. While this takes place, the transformer and the electrolytic capacitor can be too trivial.

This is the power supplies online utilized on PCs and other electronic appliances such as DVDs, VCRs and many others. It is important to comprehend that the term “switching” is an abbreviation of “high frequency switching” and has nothing to do with whether the power supply has an on/off switch or not.

The power supplies utilized on PCs executes a much better method; a closed loop system. The circuit that operates the switching transistor gets a response from the power supply outputs, thereby escalating or decreasing the duty phase of the voltage passed through the transformer in relation to the PC power utilization. This method goes by the name of pulse width Modulation (PWM). Thus, the power supplies online regulates itself depending on the power usage of the product connected to it. When the PC is not using a lot of energy, the power supply regulates itself to deliver a lower current, enabling the transformer to dispel lesser energy, thus less heat is dissipated.

Diane is the author of this article on Power supplies.
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