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A device, circuit, actuator or chemical structure which outputs a fixed voltage level is usually called with one of the following terms.

  • Voltage Source
  • Voltage Supply
  • Power Supply

Is there any technical difference between these terms or do they imply the same thing?


marked as duplicate by JYelton, user17592, placeholder, Chetan Bhargava, Daniel Grillo Oct 6 '14 at 11:17

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  • \$\begingroup\$ "Supply" is a subset of "source"; not all sources need be supplies. \$\endgroup\$ – Ignacio Vazquez-Abrams Oct 4 '14 at 16:29
  • \$\begingroup\$ To me, a Voltage Source or Current Source is a theoretical thing used in circuit simulators. Power Supply is my normal term for something capable of supplying power to a load. I don't think I'd normally use Voltage Supply. \$\endgroup\$ – Peter Bennett Oct 4 '14 at 16:42

Voltage source or Constant voltage supply or the like are the most specific. However, the vast majority of power supplies are constant-voltage, so that is what is usually assumed if you just say power supply. There are other types of power supplies, with constant current being the next most common. For example, to power LEDs you want to control current, not voltage.

If you see just power supply without a specific context or more details, you can usually assume that means a constant-voltage supply. Since something like a constant current supply is less common, that is usually explicitly stated.

  • 1
    \$\begingroup\$ Sometimes (especially in simulation or circuit theory) "voltage source" is short for "ideal voltage source" and usually "power supply" means a real world device with source impedance and finite current limit, etc. So depending on context there can be different meanings among the terms. \$\endgroup\$ – John D Oct 4 '14 at 17:34

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