Difference Between Power Source and Power Supply

Key Difference – Power Source vs Power Supply
 

Power is defined as the energy consumed or supplied within a given period. Since energy cannot be created as per the theory of conservation of energy, it should be transformed into a consumable form from an available source in order to make use of energy. Electricity is one form of the most commonly used energy forms. For electricity to be used, it should be provided or supplied to an appliance from a power supply as in the television set which is plugged into the main electricity line through a socket. But, neither the socket nor the main line produces electricity; electricity is transferred to the socket from an external energy source. As such, the key difference between power source and power supply can be identified as: the power supply is used to provide power to a device, whereas power source is the source from which the power is produced.

CONTENTS
1. Overview and Key Difference
2. What is a Power Source
3. What is a Power Supply
4. Side by Side Comparison – Power Source vs Power Supply
5. Summary

What is a Power Source?

A power source is a place where power is originated. As energy cannot be created, there is no source for all the energy in the universe, but we can identify the parent source in another form of energy. For instance, the power source of the earth can be recognized as the sun. Likewise, the source from which the electricity is produced is the power source of electricity.

Electricity is produced from different sources. Globally, the major sources of electricity production are coal, natural gas, hydropower, and nuclear energy. In addition, sources such as hydrocarbon fuel, solar energy, tidal waves, biomass fuel, wind, and geothermal energy are also used for production. Availability of the sources, cost per unit production, infrastructure, etc., are taken into account when choosing the sources for the mass production of electricity.  Furthermore, chemical compounds are used as the source in batteries such as Li-ion batteries, Ni-Cd batteries, vehicle batteries, etc.

Figure 01: World Electricity Production

Some sources like nuclear and coal are used to generate heat that boils water to produce steam that runs a steam turbine. The turbine is used with a generator which converts the kinetic energy into electricity. In all of the cases above, except in solar energy, a generator is employed to produce electricity. Solar electricity, which is produced by photovoltaic panels, is the only method that does not involve a mechanical energy transformation.

What is a Power Supply?

A power supply is a device or a method that provides electricity to a device. It does not produce electricity, but it receives electricity from an existing power line or a generator and supply controlled or uncontrolled electricity to the device. A common electric socket connected to the power lines can be considered as a simple power supply to a domestic appliance. A variety of forms of power supplies are commonly used in everyday use.

AC power supply is one type of power supply that is used to convert voltages. They are used in electric appliances so that they can be used with different supply voltages in different countries. DC power supply is another type of power supply which receives input from the AC mains to output DC voltages to electronic devices. DC power supplies also are used inside home electronic appliances. AC and DC power supplies with diverse parameters are widely used in electrical and electronic testing laboratories.

Figure 02: Basic schematic of an AC to DC power supply

Power supplies are categorized into another two types: voltage sources and current sources. The voltage source is a power supply that supplies power in a constant voltage, independent of the current drawn by the load. All of the above-mentioned examples can be considered as voltage sources since the supplied voltage is always constant. For example, the supply voltage for the socket outlet is always the same 230V. On the other hand, current sources supply a constant current to a device independent from the voltage between the two terminals. One example of a current source is the power supply in electric arc welding. The voltage of the electric arc changes with the length of the arc, but in order to have a uniform welding on the surface, the current is kept constant by the supply. Some other types of power supplies used are switch-mode power supply, programmable power supply, and uninterruptable power supply. They may include a voltage regulator, frequency converter, batteries, switches, etc. for their function of controlling voltage output in a desirable manner.

What is the difference between Power Source and Power Supply?

Summary – Power Source vs Power Supply

There are energy sources which cannot be used directly for daily tasks. However, those forms of energy can be converted into a usable form by different means. Convertible energy contains energy sources or power sources which undergo different processes to produce consumable power. On the contrary, power supplies are further used to provide electric power to devices,  taking in power which was produced from power sources. This is the main difference between power source and power supply. Power supplies have various functions, facilitating the requirements of the connected electrical and electronic devices.

Reference:
1. “Power supply.” Wikipedia. Wikimedia Foundation, 25 May 2017. Web. 26 May 2017.<https://en.wikipedia.org/wiki/Power_supply>

Image Courtesy:
1. “World Electricity Generation Pie Chart” By Delphi234 – Own work (CC0) via Commons Wikimedia
2. “ACtoDCpowersupply” By JaunJimenez at English Wikipedia (CC BY 3.0) via Commons Wikimedia

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