Definition of Power Supply are: Function, Type, Component, How it Works

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Power is the backbone of any electronic system and the power supply is what feeds the system.  Selecting the right supply can be an important difference between a device that is working at optimal levels and one that may provide inconsistent results.

 In addition to alternating current (AC) to direct current (DC) PS, DC to DC converters are also available.  If DC is already available in your system, a DC to DC converter may be a better design choice than the AC discussed below.

 PS direct current is not regulated or regulated.  Regulated supplies come in several options including linear, switch and battery-based

 Know What is a Power Supply

 A power supply is a hardware component that provides electricity to power computers and other devices.  This converts the electric current drawn from a power source, such as a wall outlet, battery or generator, to the correct format and passes it to the device.  It also regulates the voltage passed to the engine to prevent overheating. Power supply is sometimes abbreviated as PS or P/S, PSU.

 These designs are rated in terms of the number of watts they produce.  The more powerful the computer, the more watts it can deliver to components

 Power Supply Function

 Increase the voltage or decrease the voltage, by the action of a transformer, to the required ac line voltage.

 Provides multiple voltage sharing methods to meet equipment requirements.

 Convert ac voltage to pulsed dc voltage with half wave or full wave rectifier.

 Pulsed dc voltage filter to pure dc stabilized voltage for equipment use.

 Regulates the output power supply in proportion to the applied load

 Power Supply Components

 1. Transformer

 A transformer is a static device that transfers electrical energy from the primary winding to the secondary winding without affecting the frequency.  It is used to raise or lower the AC voltage level and isolate the rest of the electronic system from AC power.

 The primary winding of the transformer is connected to an AC voltage source which produces alternating current while the secondary winding is connected to the load.  The primary and secondary windings are not physically connected to each other but since electromagnetic induction follows Faraday's law, there is an induced voltage in the secondary winding.

 There are three main functions of a transformer, namely: increasing the voltage, lowering the voltage and providing isolation between the primary and secondary circuits.

 2. Rectifier

 A rectifier is a device used to convert AC power into pulsating DC.  The basic rectifier is a diode.  This diode is a unidirectional device that operates as a rectifier in the forward direction.  The three basic rectifier circuits that use diodes are the half-wave, full-wave, and full-wave bridge types.

 3. Filters

 The power supply filter is used to keep component ripples from appearing in the output.  It is designed to convert the pulsating DC of a rectifier circuit into a smooth DC level.  The two basic types of power supply filters are the capacitance filter (C-filter) and the Resistor-Capacitor filter (RC-filter).  The C-filter is the simplest and most economical filter available.  On the other hand, an RC-filter is used to reduce the amount of voltage ripple across the filter capacitor.  Its main function is to pass most of the DC component while attenuating the AC component of the signal.  The RC filter consists of a resistor and a capacitor.  RC filters are used to filter signals by only blocking certain frequencies and passing other frequencies.  Common RC filters are High-Pass filters and Low-Pass filters.

 Kinds of Power Supply

 1. AC power supply

 AC or Alternating Current has no polarity.  Its polarity changes with time according to its frequency.  In PS AC, the magnitude and direction of the current also change over time.

 Source: The main source of PS AC is an alternator which is an electric machine that can convert mechanical energy into alternating electrical energy.

 The use of AC power supply with standard frequency voltage is mainly used to operate electrical equipment such as electric motors, fans, air conditioners, pumps, refrigerators, etc.

 2. DC Power Supply

 PS DC has a fixed polarity.  In PS DC, the magnitude and direction of the current do not change with time.  DC has no power factor and no frequency.

 Source: PS DC sources are Batteries, Solar Panels, etc.  Moreover, we can convert AC to DC using a rectifier circuit.

 Applications: Electronic circuits and devices mostly use PS DC such as Computers, Printers, Televisions, Music Players, etc.

 3. Power Supply Without Transformer

 PS without a transformer does not have a transformer for voltage reduction purposes so it is called a power supply without a transformer.  Here a series capacitor is used to step down the 230V AC supply to the required voltage level.  Series capacitors lower the voltage.

 4. SMPS Power Supply

 Switched Mode Power Supply or SMPS is an electronic power supply in which, semiconductor devices such as MOSFETs, IGBTs convert AC to DC or DC to AC by a high-speed switching mechanism.

 In SMPS, Pulse Width Modulation (PWM) technique is used for the purpose of high speed switching.  By varying the duty cycle, the output voltage can be changed according to our needs.

 5. UPS Power Supply

 An Uninterruptible Power Supply is an electrical PS designed to provide power to a load during emergency purposes or when the main input fails.  This system uses electrical energy storage devices such as batteries, supercapacitors to store electrical energy.

 6. Regular Power Supply

 Regulated Power Supply (RPS) is an electronic circuit designed for variable loads to produce a stable direct current and maintain a constant voltage across the load.  Regulated power supply circuits always maintain a constant voltage across the load by changing the input current.

 7. Linear Power Supply

 Linear PS is an electronic circuit designed to convert a variable DC supply into a constant DC supply.  It takes a variable DC supply in the input and provides a stable DC supply in the output.  Linear circuits have a current limiting function as well.

 Conclusion

 Power Supply can be either internal or external.  Most desktop computers have an internal power supply that connects directly to the motherboard.  Smaller devices, such as laptops or external hard drives , use an external PS to charge the built-in battery