LED low voltage power supply, power supply voltage
between 6-24V, depending on the product, so it is safer than the use of
high-voltage power supply power supply, particularly in public places.
Efficacy
Energy consumption reduced by 80% than the same
luminous efficiency of incandescent
Applicability
Very small, small piece of each unit LED is 3-5mm
square, so the device can be fabricated into various shapes, and is suitable
for the environment variable
Light-emitting diodes
Stability
100,000 hours, the light fades to 50% of the
initial
Response time
Incandescent response time of milliseconds, the
response time of the LED lights for a nanosecond
Of environmental pollution
No harmful metallic mercury
Color
Materials of light-emitting diodes by chemical
modification methods, adjusting the energy band structure and band gap, red
yellow blue orange multicolor light. Red tube voltage is small, different
colors of red, orange, yellow, green, and blue light-emitting diode operating
voltage is increased successively.
Price
LED price is now more and more civilians, due to
the LED power-saving features, perhaps in the near future, people are the
incandescent LED lights. Now, some cities in our country roads, schools,
factory and other places have switched to the the Wan LED street light,
energy-saving lamps.
Monochromatic LED types and history of the
development
The LED light source made of the earliest
applications of semiconductor PN junction light-emitting principle is
introduced in the early 1960s. Use at the time material is GaAsP, red (λp =
650nm), the drive current of 20 mA, the luminous flux is only thousandths of a
few lumens, luminous efficiency of about 0.1 lm / W
The mid-1970s, the introduction of elements of In
and N, generated by the LED green (λp = 555nm), yellow (λp = 590nm) and orange
(λp = 610nm), luminous efficiency is also increased to a lumens / watt.
To the early 1980s, there has been a GaAlAs LED
light source, the red LED luminous efficiency of 10 lumens / watt.
The early 1990s, of red, yellow the GaAlInP and
green, blue GaInN two new materials successfully developed, so that the LED
luminous efficiency has been greatly improved. In 2000, the former is made of
LED in red, orange District (λp = 615nm) light efficiency of 100 lm / W, while
the latter is made of LED luminous efficiency in the green region (λ p = 530nm)
can reach 50 lm / watts.
Monochromatic LED applications
Light-emitting diodes
The initial LED as the light of the instructions of
the instrumentation, then a variety of light-colored LEDs in traffic lights and
a large area display a wide range of applications, resulting in a good economic
and social benefits. To 12 inches of red traffic lights, for example, in the
United States was long-lived, low-efficiency 140-watt incandescent lamp as a
light source, it produces 2000 lumens of white light. The red filter, the light
loss of 90%, leaving only 200 lumens of red light. In the light of the new
design, Lumileds uses 18 red LED light source, including circuit losses, the
total power consumption of 14 watts to produce the same luminous efficiency.
The car lights are also an important area of the LED light source applications. 1987, China
began to be installed in the car CHMSL LED response
speed (nanosecond), an early stage so that the trailing vehicle drivers know
that driving conditions to reduce rear-end accidents.
In addition, LED lights in the
outdoor red, green, blue full-color display, mini flashlight key chain field
have been applied.
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