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Power Supplies A to Z : "V"

We've included this handy glossary to help with the terminology & abbreviations relating to power products. Pick a letter below to begin.

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 #

V

Abbreviation for volt.

VA

Abbreviation for volt-ampere.

Vac

Acronym for volts of alternating current

Variable Resistor

See Potentiometer.

Varistor

Combination of Variable Resistor. A two-electrode semiconductor device having a non-linear, voltage-dependent resistance (usually a high resistance at low voltages and low resistance at high voltages). Often used to protect circuits against transient voltages.

Schematic Symbol for a Varistor

Varnish Dip

The process of dipping a transformer or coil in varnish to bind or protect materials.

Vcc

Voltage Collector Collector. Positive supply voltage of a Bipolar Junction Transistor. The doubled suffix indicates that the voltage is common. i.e. it is the supply voltage to one (or more) collectors and not just the voltage at a specific collector.

Vdc

Acronym for volts of direct current

Vdd

Voltage Drain Drain. Positive supply voltage of a Field Effect Transistor. The doubled suffix indicates that the voltage is common. i.e. it is the supply voltage to one (or more) drains and not just the voltage at a specific drain.

VDE

Abbreviation for Verband Deutscher Elektrotechniker.

VDR

Abbreviation for Voltage Dependent Resistor.

Vee

Voltage Emitter Emitter. Negative supply voltage of a Bipolar Junction Transistor. The doubled suffix indicates that the voltage is common. i.e. it is the supply voltage to one (or more) emitters and not just the voltage at a specific emitter.

Verband Deutscher Elektrotechniker (VDE)

German organisation charged to test and to evaluate products, including power sources. See http://www.vde.com/vde_en/

Vias

See Plated Through Hole.

Volt (V)

Unit of measurement of electromotive force or potential difference. Symbol E, in electricity; symbol V in semiconductor circuits. A current of 1 A passing through a resistance of 1 ohm will produce a potential difference of 1 volt. See Ohm's Law. Written as 'volt'. Abbreviated to V.

Volt Microsecond / Volts per Microsecond

Rate of change of voltage over a period of time expressed in volts/microseconds.

Volt Second

In a control circuit, the on-time x the voltage applied to the winding is controlled (effectively running the magnetic component at peak magnetic flux density).

Volt Second Clamp

A circuit in the control of the pulse width modulator located in the primary which terminates the pulse when the volt seconds applied to the primary of the transformer exceeds a predetermined value.

Voltage

A derivative electrical quantity, E, measured in the units volts and defined in terms of the independently obtained ampere, I, and the unit or Resistance, ohm (R) by Ohm’s Law E=IR.

Voltage Balance

The difference in magnitude, in percent, between differential tracking output voltages of a power supply (PSU) where the voltages have equal nominal values with opposite polarities.

Voltage Clamp

See Clamp Circuit

Voltage Dependent Resistor

Another name for Varistor.

Voltage Divider

Tapped or series resistance or impedance across a source voltage to produce a lower output voltage.

Voltage Drop

Difference in potential between two points in a passive component or circuit.

Voltage Limit

Maximum or minimum value in a voltage range.

Voltage Limiting

Bounding circuit used to set specified maximum or minimum voltage levels.

Voltage Regulation

The process of holding voltage constant between selected parameters, the extent of which is expressed as a percent. See also Regulation.

Voltage Source

A power source that delivers constant voltage.

Voltage Stabilisation

The use of a circuit or device to hold an output voltage constant within given limits.

Volt-Ampere (VA)

Unit of Apparent Power.

Vss

Voltage Source Source. Negative supply voltage of a Field Effect Transistor. The doubled suffix indicates that the voltage is common. i.e. it is the supply voltage to one (or more) sources and not just the voltage at a specific source.

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 #