Power Supply Technology Glossary
AC Input: Alternating Current (AC) input is the typical wall power that is regulated by a transformer and rectified.
Active Clamp: An active clamp is an electronic circuit that uses transistors to “clamp” the output voltage of a power supply. It is designed to reduce voltage spikes and noise on the output of a power supply.
Active Power Factor Correction: Active Power Factor Correction (PFC) is a power supply feature that improves power factor (PF) by enhancing the input current waveform. This helps to reduce harmonics of the current waveform, making it more sinusoidal.
Angular Misalignment: Angular misalignment is an error in the output voltage of a power supply caused by a misalignment in the angle of the voltage waveforms between input and output.
Battery Backup: A battery backup system is an uninterruptible power supply (UPS) that provides temporary electrical power when the primary supply is interrupted.
Capacitance: Capacitance is a type of static electric charge stored in an electric field. Capacitance is measured in farads.
Capacitor: A capacitor is an electrical component that stores charge and releases it when necessary. Capacitors are used in power supplies to regulate current and voltage.
Current: Current is the rate of movement of electric charge through a conductor, usually expressed in amperes.
DC Input: DC input is direct current provided from a source such as a battery or solar cell.
DC Output: DC output is power supplied from a power supply to a load in the form of direct current.
Diode: A diode is an electrical component that only allows current to flow in one direction. It is used to protect power supplies by preventing reverse current flow when the input voltage is reversed.
Drive: A drive is a component in a power supply that amplifies the current or voltage in order to convert AC power to DC power.
Dynamic Headroom: Dynamic headroom is a measure of a power supplys ability to respond to rapid fluctuations in its load.
Efficiency: Efficiency is a measure of how much of the power input to a power supply is actually converted to useful output power.
EMI/RFI: EMI/RFI stands for electromagnetic interference/radio frequency interference. It is unwanted energy emitted from an electrical component, such as a power supply, that can interfere with other nearby devices or equipment.
Fault Protection: Fault protection is a feature of a power supply that monitors the output and shuts down if an over-voltage, over-current, or short circuit condition occurs.
Fault Tolerance: Fault tolerance is a power supply feature that enables the output to continue operating even if a minor fault occurs within the power supply.
Fuse: A fuse is an electrical component that is designed to break the current path when overloaded with current, protecting the power supply from damage.
Ground/Earth: Ground/earth is an electrical connection specified in the power supply spec that is designed to provide additional protection against electric shock.
Heat Sink: A heat sink is a device that is designed to dissipate heat away from a component, usually used in conjunction with power supplies to keep the output stage cool.
Hold-up Time: Hold-up time is the time a power supply can continue to supply power to the load, after a momentary interruption in an AC input line.
Inrush Current: Inrush current is the high current a power supply initially draws when first energized.
Isolation: Isolation refers to a power supplys ability to maintain a dielectric barrier between its input and output power rails.
Leakage Current: Leakage current is the amount of current that leaks through the insulation in a power supply.
Line Regulation: Line regulation is a measure of the power supplys ability to maintain a constant output voltage, even with fluctuations in the input line voltage.
Load Regulation: Load regulation is a measure of the power supplys ability to maintain a constant output voltage, even with fluctuations in the output current level.
Magnetics: Magnetics are components used in a power supply to convert AC power to DC power. They have both a transformer and inductor.
