Power Supply (Electro)

• Power supply


  An electrical device that supplies electric power to an electrical load
• Main purpose of a power supply

  To convert electric current from a source to the correct voltage, current, and frequency to power the load
• Categories of power supply

  • Regulated power supply
  • Unregulated power supply
  • Adjustable power supply
  • Isolated power supply
• Regulated power supply


  Maintains constant output voltage or current despite variations in load current or input voltage
• Unregulated power supply


  Changes significantly when its input voltage or load current changes
• Adjustable power supply


  Allows the output voltage or current to be programmed by mechanical controls or by means of a control input, or both
• Isolated power supply


  Has a power output that is electrically independent of its power input
• Types of power supply

  • DC power supplies
  • Linear power supply
  • Switched-mode power supply (SMPS)
  • Capacitive (transformerless) power supply
  • Linear regulator
  • AC power supplies
  • AC adapter
  • Programmable power supply (PPS)
  • Uninterruptible power supply (UPS)
  • High-voltage power supply
  • Bipolar power supply
• DC power supplies


  An AC-to-DC power supply operates on an AC input voltage and generates a DC output voltage. A DC power supply operating on DC input voltage is called a DC-to-DC converter.
• Linear power supply


  The AC input voltage passes through a power transformer and is then rectified and filtered to obtain a DC voltage
• Switched-mode power supply (SMPS)


  The AC mains input is directly rectified and then filtered to obtain a DC voltage. The resulting DC voltage is then switched on and off at a high frequency by electronic switching circuitry, thus producing an AC current that will pass through a high-frequency transformer or inductor.
• Capacitive (transformerless) power supply


  Uses the reactance of a capacitor to reduce the mains voltage to a smaller AC voltage. The resulting reduced AC voltage is then rectified, filtered and regulated to produce a constant DC output voltage.
• Linear regulator


  Converts a varying DC voltage to a constant, often specific, lower DC voltage. They often provide a current limiting function to protect the power supply and load from overcurrent.
• AC power supplies


  Typically takes the voltage from a wall outlet (mains supply) and uses a transformer to step up or step down the voltage to the desired voltage. They can also be used to change the frequency and voltage.
• AC adapter


  A power supply built into an AC mains power plug. AC adapters typically have a single AC or DC output, but some have multiple outputs. "Universal" AC adapters have interchangeable input connectors to accommodate different AC mains voltages.
• Programmable power supply (PPS)


  Allows remote control of its operation through an analog input or digital interface. Controlled properties may include voltage, current, and frequency. They are used in a wide variety of applications, including automated equipment testing, crystal growth monitoring, semiconductor fabrication, and x-ray generators.
• Uninterruptible power supply (UPS)


  Takes its power from two or more sources simultaneously. It is usually powered directly from the AC mains, while simultaneously charging a storage battery. Should there be a dropout or failure of the mains, the battery instantly takes over so that the load never experiences an interruption.
• High-voltage power supply


  Outputs hundreds or thousands of volts. A special output connector is used that prevents arcing, insulation breakdown and accidental human contact. They are commonly used to accelerate and manipulate electron and ion beams in equipment such as x-ray generators, electron microscopes, and focused ion beam columns, and in a variety of other applications, including electrophoresis and electrostatics.
• Bipolar power supply


  Operates in all four quadrants of the voltage/current Cartesian plane, meaning that it will generate positive and negative voltages and currents as required to maintain regulation. When its output is controlled by a low-level analog signal, it is effectively a low-bandwidth operational amplifier with high output power and seamless zero-crossings. This type of power supply is commonly used to power magnetic devices in scientific applications.