AC
Current that flows in alternating directions between two points. See also AMP, Current
and DC.
AC/AC Adapter
Adapter that has an AC voltage input and an AC voltage output.
AC/DC Adapter
Adapter that has an AC voltage input and an DC voltage output.
Adapter
Electrical device that can take an AC voltage input and transform it into a
different (or multiple) AC or DC voltage outputs.
Ambient Temperature
Temperature that the adapter will operate in.
AMP
Ampere...which is a measure of current. Can be abbreviated by either
"Amps", "A", or expressed as milliamps (mA). See MilliAmps below..
CE
The European safety agency approval mark signifying approval to low voltage
testing.
Core Loss
This is the measure of power drawn by the input winding of a unit even when not in
use (before load is applied).
cUL
Underwriter's Laboratory has been granted the ability to test and approve
electrical devices for use in Canada. Units marked with the cUL mark have been
tested by UL for use in Canada (and are fully recognized by Canada).
Current
The measure of current is expressed in AMPs.
Current can either flow consistently in one direction (DC current), or can reverse/
alternate directions (AC current).
DC
Current that flows in the same direction between two points. See also AMP, Current
and AC.
Efficiency
Ratio of output power compared to input power.
Exciting Current
This is the measure of current drawn through the input winding of a unit even when
not in use (before load is applied). See also Core
Loss.
Frequency
Measures the number of times that a flow of current changes direction in one
second. Expressed as Hertz (Hz). Most
North and South American locations operate on an input of 60Hz while most of Europe has a
50Hz input.
Hertz
Measure of frequency. Usually expressed as Hz. See Frequency.
Hi-Pot (High Potential)
Used to confirm if the break-down voltage of a unit's internal insulation exceeds
the minimum requirement. Testing is done by applying high voltage between two
isolated points such as primary to secondary, primary to ground, or secondary to
ground for a very brief period.
Impedance
Ratio of voltage to current expressed in ohms. This measurement shows the
resistance to the AC current flow. Impedance between circuits must
be matched in certain design situations. See also OHM.
Inherently Limited
Input
This is the voltage and frequency applied to the primary of a unit. For example, 120Volts 60Hz,
240Volts 50Hz, and so on.
Inrush Current
Peak instantaneous input current drawn by a unit upon the initial application of
input voltage.
Isolation
Where there electrical separation between the primary
and secondary windings. This safety
feature helps eliminate the possibility of shock.
Leakage Current
The AC or DC
current going from the input to output (and/or
chassis) of an isolated power supply at a specified voltage.
MilliAmps
Measure of AMPs expressed as 1000 times
Amps. For example .5Amps would be 500mA (.5 x 1000).
MTBF
Calculated failure rate of a power supply given in hours.
Nominal
Objective for a specified parameter...may not be the actual value measured.
OHM
The ratio of voltage to current is expressed in ohms. This measurement
shows the resistance to the AC current flow. Impedance (or the number of measured
ohms) between circuits must be matched in certain design situations. See also Impedance and Resistance.
Open Circuit
When a circuit has been broken so that conducting components do not allow for the
flow of current, the circuit is said to be
open. This condition can either be intentional (to provide protection), or
unintentional (such as when a wire breaks).
Output
The value in voltage and current at the output connections of a unit.
Overload Protection
Function of a power supply that automatically shuts down the supply in the event of
reaching a predetermined excessive output current.
Overvoltage Protection
Function of a power supply that automatically shuts down the supply in the event of
reaching a predetermined excessive voltage.
Parallel
Peak to Peak
Primary
A winding to which the input voltage is
applied. This winding then powers the secondary
winding to generate an output voltage.
Rectification
Conversion of AC currents and voltages into DC currents and voltages. Typical
rectifications are: half-wave, full-wave and bridge.
Regulation (Line)
The change in the output voltage resulting from a change in the input voltage.
Regulation (Load)
The change in the output voltage resulting
from a change in the load resistance.
Resistance
This measurement shows the resistance to the AC current flow measured in ohms.
See also Impedance and OHM.
Ripple
The magnitude of a unit's output AC voltage.
RMS
Secondary
Generates an output voltage and current when voltage is applied to the primary winding.
Series
Short Circuit Protection
Function of a unit that limites the output current under short-circuit conditions
so that the unit can avoid being damaged.
Switching Power Supply
Temperature Rise
Measure of the heat generated by a unit at a given ambient temperature. See
also Ambient Temperature.
Thermal Protection
A feature that shuts down the unit in the event of excessive thermal
(temperature) conditions. Usually accomplished with a one-shot or resettable
fuse.
TUV
The safety agency approval mark accepted in Europe.
T-Mark
The safety agency approval mark accepted in Japan.
UL
The safety agency approval mark accepted in the U.S.A.
Universal Input
A feature of a power supply to accept a relatively wide range of input voltages. The supply can either
automatically adjust for the changed input or have a manual switch to do so.
VA
Volt Amperes
(power). Is the output voltage multiplied by
the output current. For instance, and ouput of 12V @ .5A = 6VA.
VAC
Statement of the voltage requirement. For example an input of 120VAC is 120Volts at AC current.
VDC
Statement of the voltage requirement. For example an output of 4VDC is 4Volts
at DC current.
Volt
Measurement of voltage which is required to move a certain number of electrons from
one point to another. When the voltage moves in one direction it is DC volts and when it alternates direction, it is AC volts.
Watt
Measurement of power determined by multiplying the output current
by the output voltage.
- Anything we forgot? Please let us know if there are other definitions you
would like added to this page:
Enterprise Electronics Corporation