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Power Supplies A to Z : "m"

We've included this handy glossary to help with the terminology & abbreviations relating to power products. Pick a letter below to begin, or download the glossary to refer to it whenever you like.

A B C D E F G H I J K L M N O P Q R S T U V W X-Z #

Magnetic Amplifier (Mag Amp)

Part of the output control for a power supply. A special type of inductor with a very square hysteresis loop. Used as a regulating switch to control the output voltage.

Magnetic Gap

See Air Gap

Margining

Adjusting the output voltage by a specified amount for system testing or other use.

Master/Slave Operation

Two or more regulated power supplies connected such that one (the master) controls the others (the slaves).

Maximum Load

1) The highest allowable output rating specified for any or all outputs of a power supply (PSU) under specified conditions including duty cycle, period and amplitude.

2) The highest specified output power rating of a power supply (PSU) specified under worst case conditions.

Mean Time Between Failure (MTBF)

The average length of time between system failures, exclusive of infant mortality and rated end-of-life. Established methods of calculating MTBF are described in the most recent edition of Mil Handbook 217 or according to Telcordia. Two key factors which affect the MTBF are the ambient temperature at which the power supply is used and the component count. Adding components that actually increase the reliability of a unit (such as clamping diodes, snubbers, etc.) can lower the calculated MTBF figure. It is important to note that this figure is vulnerable to 'specmanship' from some manufacturers who may wish to make their power supplies look better than they should be.

MEG

Acronym for Multiple Efficiency Gain.

Mega

SI prefix multiplier. Multiplies by 106. So 1 MHz = 1 x 106 Hz = 1000000 Hz. Written as 'mega'. Abbreviated to 'M'.

Metal Oxide Semiconductor Field Effect Transistor (MOSFET)

A type of Field Effect Transistor whose channel is insulated from its gate with an insulator(typically SiO2). It is the most commonly used type of FET and is used in all CMOS circuits. 

Schematic Symbols for an MOSFETs

Metal Oxide Varistor (MOV)

Common type of Varistor. A two terminal device with a resistance which is high at low voltages and low at high voltages.

Mho

Obsolete (now replaced bysiemens) unit of measurement of Conductance.

Micro

SI prefix multiplier. Multiplies by 10-6. So 100 µF = 100 x 10-6 F = 0.0001 F. Written as 'micro'. Abbreviated to 'µ'.

Milli

SI prefix multiplier. Multiplies by 10-3. So 100 mF = 100 x 10-3 F = 0.1 F. Written as 'milli'. Abbreviated to 'm'.

Minimum Load

The lowest current that must be drawn from a power supply (PSU) for the power supply to operate within specification.

Minimum Operating Temperature

The lowest ambient temperature at which the power supply (PSU) will continuously operate safely and within specifications.

Minimum Startup (or Starting) Temperature

The lowest ambient temperature at which a power supply (PSU) will turn on and operate safely (although not necessarily to full specification).

Minus (-)

Negative terminal of a power supply (PSU).

Modular Power Supply

A power supply (PSU) made up of a number of separate building blocks such as output modules. Each module is usually selectable to closely match the requirements. Normally, each module is galvanically isolated. TDK-Lambda's Vega, NV-350 & NV 700 are industry leading examples of modular power supplies.

MOSFET

Acronym for Metal Oxide Semiconductor Field Effect Transistor.

MOV

Abbreviation for Metal Oxide Varistor.

MRT

Abbreviation for Multi-Resonant Topology

MTBF

Abbreviation for Mean Time Between Failure.

MTTR

Abbreviation for Mean Time to Repair. 

Multimeter

A meter capable of measuring current, voltage and resistance.

Multiple Efficiency Gain

A technology introduced with TDK-Lambda's NV-Power range of products to achieve industry leading efficiency for multiple-output power supplies. Efficiency improvements at various stages of the power supply multiply together producing the compound effect of Multiple Efficiency Gain.

Multiple Output Power Supply

A power supply (PSU) with two or more outputs.

Multi-Resonant Topology (MRT)

A switched mode power supply topology used in modern design, high efficiency, switched mode power supplies. Rather than using magamp post regulators and two-stage conversion, MRT uses closed loop control of the main outputs, a single conversion stage and auxiliary channels employing high efficiency dc-dc post regulation. The inherent low internal voltages on the secondary side allow the use of low voltage synchronous rectifiers with much lower losses, thus improving the efficiency. This topology allows the use of smaller inductors and wound components. The use of MRT over more traditional magamp regulation can offer up to 5% efficiency improvement for multiple output power supplies. TDK-Lambda's NV-Power range utilises MRT to provide units which have high efficiency.

A B C D E F G H I J K L M N O P Q R S T U V W X-Z #

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