What is the full form of SMPS, used in computers and electronics?

SMPS stands for "Switched-Mode Power Supply" (also called a "switching power supply").

What an SMPS does:

It converts electrical power from one form to another, usually from the alternating current (AC) mains supply (230 V in India) into the low-voltage direct current (DC) needed by electronic devices, such as +12 V, +5 V and +3.3 V in a computer.

How it works:

Unlike a traditional "linear" power supply, which uses a large transformer and wastes extra energy as heat, an SMPS uses high-speed electronic switches (transistors such as MOSFETs) that turn on and off thousands of times per second.

The switching action, along with small transformers, inductors and capacitors, converts and regulates the voltage efficiently.

Advantages of SMPS:

• High efficiency, usually 70-95 per cent, so less energy is wasted as heat.
• Small size and light weight, because high-frequency transformers are much smaller.
• Works with a wide range of input voltages.

Disadvantages:

• More complex circuits.
• Can produce electrical noise (electromagnetic interference), which must be filtered.

Uses of SMPS:

Desktop computers (the power supply unit, PSU, is an SMPS), laptop chargers, mobile phone chargers, LED TVs, LED lights, routers and other electronic devices.

Related terms:

• UPS: Uninterruptible Power Supply (provides backup power from a battery during power cuts).
• AC: Alternating Current; DC: Direct Current.
• PSU: Power Supply Unit.
• Computer power supplies often carry an "80 PLUS" certification for energy efficiency.
• In India, the Bureau of Energy Efficiency (BEE) gives star labels to some electrical appliances.

Why not the other options?

• ✗"Simple Mode Power System" is not the correct expansion.
• ✗"Standard Main Power Source" is not the correct expansion.
• ✗"Static Mode Power Supply" is not the correct expansion.