 12 Volt & 110 Volt
Converters, Inverters, Adapters
& Battery Chargers
Whether you're traveling in the car, or at home, we have
the products to invert and convert just about any voltage. Adapters convert
the plug type and voltage for battery operated products. Converters switch
power from 110 volts to both up and down conversion. Inverters change your
cars 12 volt power into 110 volt so you can power any type of household
product.
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Turn 120
Volts
Into
12, 9 ,6, or 3 Volts |
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Turn Car
12 Volts Into
9, 6 or 3 Volts |
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Turn Car
12 Volts
Into 120 Volts |
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120 Volt
Converter Adapter
B41-1745 |
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12
Volt DC to DC
Adapter
B41-1750 |
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DC to AC
400 Watt
Power Inverter
B41-1751 |
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"Portable Power"
Cell Phone & IPOD Charger
Powers Any 12 Volt Device |
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Rapid AA AAA Battery Charger Pack |
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Digital
NiMh AA
Battery Charger |
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12 Volt
Power Pack
Car & USB Adapters
B41-1820 |
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Rapid AA & AAA Battery Charger Pack
B41-1404 |
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Digital AA
NiMh Battery Charger
B41-1403 |
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How AC/ DC
power supplies work
In the past mains electricity was supplied as DC in some regions, AC in
others. Simple, cheap, linear power supplies running directly from
either AC or DC mains, often without a transformer used. They used a
rectifier and capacitor filter; the rectifier was essentially a
conductor, having no sudden effect when operating from DC.
A computers switched mode power supply unit.A switched-mode power supply
(SMPS) works on a different principle. AC mains input is directly
rectified without the use of a transformer, to obtain a DC voltage. This
voltage is then sliced into small pieces by a high-speed electronic
switch. The size of these slices grows larger as power output
requirements increase.
The input power slicing occurs at a very high speed (typically 10 kHz —
1 MHz). High frequency and high voltages in this first stage permit much
smaller step down transformers than are in a linear power supply. After
the transformer secondary, the AC is again rectified to DC. To keep
output voltage constant, the power supply needs a sophisticated feedback
controller to monitor current draw by the load.
Modern switched-mode power supplies often include additional safety
features such as the crowbar circuit to help protect the device and the
user from harm.[1] In the event that an abnormal high current power draw
is detected, the switched-mode supply can assume this is a direct short
and will shut itself down before damage is done. For decades PC computer
power supplies have also provided a power good signal to the motherboard
which prevents operation when abnormal supply voltages are present.
Switched mode power supplies have an absolute limit on their minimum
current output. [2] They are only able to output above a certain wattage
and cannot function below that point. In a no-load condition the
frequency of the power slicing circuit increases to great speed, causing
the isolation transformer to act as a tesla coil, causing damage due to
the resulting very high voltage power spikes. Switched-mode supplies
with protection circuits may briefly turn on but then shut down when no
load has been detected. A very small low-wattage dummy load such as a
ceramic power resistor or 10 watt light bulb can be attached to the
supply to allow it to run with no primary load attached.
Power factor has become a recent issue of concern for computer
manufacturers. Switched mode power supplies have traditionally been a
source of power line harmonics and have a very poor power factor. Many
computer power supplies built in the last few years now include power
factor correction built right into the switched-mode supply, and may
advertise the fact that they offer 1.0 power factor.
By slicing up the sinousoidal AC wave into very small discrete pieces,
the portion of the AC current not used stays in the power line as very
small spikes of power that cannot be utilized by AC motors and results
in waste heating of power line transformers. Hundreds of switched mode
power supplies in a building can result in poor power quality for other
customers surrounding that building, and high electric bills for the
company if they are billed according to their power factor in addition
to the kilowatts used. Filtering capacitor banks may be needed on the
building power mains to suppress and absorb these negative power factor
effects.
Uninterruptible power supply
Main article: Uninterruptible power supply
An Uninterruptible Power Supply (UPS) takes its power from two or more
sources simultaneously. It is usually powered directly from the AC
mains, while simultaneously charging a storage battery. Should there be
a dropout or failure of the mains, the battery instantly takes over so
that the load never experiences an interruption. Such a scheme can
supply power as long as the battery charge suffices, e.g., in a computer
installation, giving the operator sufficient time to effect an orderly
system shutdown without loss of data. Other UPS schemes may use an
internal combustion engine or turbine to continuously supply power to a
system in parallel with power coming from the AC mains. The
engine-driven generators would normally be idling, but could come to
full power in a matter of a few seconds in order to keep vital equipment
running without interruption. Such a scheme might be found in hospitals
or telephone central offices.
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