Glossary


TERMS AND ACRONYMS CONTINUED..
See below for the special

Leakage current: Current flowing between the output buses and chassis ground due to imperfections in electronic components and designs. It must be tightly controlled to satisfy safety regulations such as UL and VDE.

Line regulation: The variation of an output voltage due to a change in the input voltage, with all other factors held constant. Line regulation is expressed as the maximum percentage change in output voltage as the input voltage is varied over its specified range.

Linear power supply is a PSU that regulates the output parameter (usually output voltage) by varying voltage drop accross an electronic component placed in series with the load which dissipates unused power. This component may be a power semiconductor or a resistor. The regulation is accomplished by changing its effective resistance (if it is a power semiconductor) or by forcing extra current through it (if it is a resistor).

Linear regulator: A common voltage stabilization technique in which the control device (usually a transistor) is placed in series or parallel with the power source to regulate the voltage across the load. The term “linear” is used because the voltage drop across the control device is varied continuously to dissipate unused power.

Load: For voltage regulated power supplies, the load is the output current.

Load regulation: Variation of the output voltage due to a change in the output’s load within a specified range with all other factors held constant. It is expressed as a percentage of the nominal DC output voltage.

Logic inhibit: The ability to turn a power supply off and on with TTL signals. A logic low generally allows the power supply to operate. A logic high turns off the power supply. See also: Logic low.

Logic low: A TTL voltage lower than 0.8 V. Also known as a “logic 0″.

Master/Slave operation: In order to increase output power and provide redundancy should one converter fail, several converters are often connected in parallel. In most cases one type of converter is then used as master, controlling the other (slave) converters.

Modular: A physically descriptive term used to describe a power supply made up of a number of separate subsections, such as an input module, power module, or filter module. Modular construction tends to lower the MTBF.

MTBF This measurement, expressed in hours, gives the relative reliability, and can be based on actual operation or on a calculated standard such as MIL

Multiple output supply: A power supply that delivers two or more different output voltages.

Noise: Noise is a periodic, random component of undesired deviations in output voltage. Usually specified in combination with ripple. See: PARD and also: Ripple.

Nominal output voltage: The intended, ideal voltage of any given output.