Currently in the general LED lighting market, there are non-isolated designs and isolated drive power. Non-isolated designs are limited to dual-insulation products, such as replacements for light bulbs, where the LED and the entire product are integrated and sealed in a non-conductive plastic, so the end user does not have any risk of electric shock. Secondary products are isolated and relatively expensive, but they are essential where the user can access the LEDs and output wiring (usually in the case of LED lighting and street lighting applications). An LED driver with an isolating transformer or electrically isolated means that the LED can be touched directly without touching the battery. The LED drive power without the isolation transformer can still achieve partial mechanical insulation by means of the protective casing, but the LED at this time cannot be directly contacted during operation. Insulated bulbs will become mainstream in the future The physical design determines whether the drive is isolated or non-isolated. Security rules usually require the use of two separate isolation layers. Designers can choose between two physical barriers, a plastic diffuser and a glass shield, and use a non-isolated power supply. If physical isolation costs are too high, there are mechanical difficulties, or too much light is absorbed, electrical isolation issues must be addressed in the power supply. Isolated power supplies are typically larger than non-isolated power supplies of the same power level. Lighting designers must perform significant cost and design optimizations in each of the products they design. Since it is suitable for different applications, whether it is an isolated insulating transformer or an isolated protective lamp housing, the designer will always have different opinions in different angles. Often, they analyze in many ways, such as cost and manufacturing processes, efficiency and volume, insulation reliability and safety specifications, and so on. The drive with transformer has higher cost, but it also makes the LED luminaire more practical and can meet the needs of end users accidentally touching the LED. An ordinary E27 model bulb can be replaced with an LED lamp when the incandescent glass housing is easily damaged. In addition, luminaires in industrial areas or office equipment applications do not need to reach end users, such as street lights and mall lighting, where LED lights do require isolation transformers. As a product that can be safely used by end users, the reliability of insulation and isolation must be considered. As a complete product, the parts of the product surface that are accessible to the user must be isolated and not subject to electric shock. From the perspective of the entire system, isolation is inevitable, the only difference is the location of the isolation. Some designers use isolated transformer designs so they can simplify heat dissipation and lampshade design. If a non-isolated drive design is used, reliable insulation requirements must be considered for structures such as lamp housings. Therefore, as a power driver, both isolated and non-isolated solutions exist simultaneously. The main challenge that Chinese LED driver manufacturers may face is finding low-cost AC/DC drivers to achieve tighter power factor and efficiency performance in low-cost power systems. In the future, the use of high-quality, high-reliability power supplies in systems where space is limited and where heat dissipation is difficult (such as LED luminaires) will no longer be free. However, before the end user has used many of the bulbs that last for about 10,000 hours, it is quite difficult to prove that the quality is high. Transformer-based isolated LED driver power supply will be the mainstream Both isolated and non-isolated LED drive power solutions have advantages and disadvantages. The industry believes that Class II will be the mainstream because it simplifies LED cooling. Class I or II systems rely on grounding systems and, in most cases, are closely related to the installation location. Class II is more common, requiring two-stage or reinforced isolation, which requires transformer magnetic windings, insulation tapes, and physical isolation. The ClassI system requires a grounded enclosure and/or mechanical barrier that is not required by the Class II system. There are several trends currently driving the development of the LED lighting market. The first is the continuous improvement of high-brightness LED efficiency and the emergence of highly efficient high-reliability constant-current LED drive power, followed by global legislation prohibiting incandescent lighting (due to its low efficiency) and the gradual fading out of CFL energy-saving lamps (if broken) If it does, it will emit mercury that is harmful to the environment). The combination of these factors is making LED lighting a long-term trend. Of course, low system costs (including LEDs, thermal management systems, and LED drivers) are always the driving force for consumers to adopt LED general lighting. In fact, in many LED lighting products, failure is a common phenomenon, mostly because of power failure, not LED failure. At the design level, this means that the OEM must become an expert in system thermal design. LEDs provide high efficiency, but they also generate more heat transfer than incandescent or energy-saving lamps. Since many LED lighting applications are enclosed in a small space, it is difficult to dissipate heat by ventilation. Without careful thermal design, LEDs and power drive circuits can easily degrade or permanently fail due to high temperatures. —————————————————————————— MCU related data collection - smart big era low-power MCU pilot
A rice cooker or rice steamer is an automated kitchen appliance
designed to boil or steam rice. It consists of a heat source, a cooking bowl,
and a thermostat. The thermostat measures the temperature of the cooking bowl
and controls the heat. Complex rice cookers may have many more sensors and
other components, and may be multipurpose. Cooking rice has traditionally
required constant attention to ensure the rice was cooked properly, and not
burnt. Electric rice cookers automate the process by mechanically or
electronically controlling heat and timing, thus freeing up a heating element
on the cooking range that had to be otherwise occupied for rice cooking.
Although the rice cooker does not necessarily speed up the cooking process,
with an electric rice cooker the cook's involvement in cooking rice is reduced
to simply measuring the rice, preparing the rice properly and using the correct
amount of water. Once the rice cooker is set to cook, the rice will be cooked
with no further attention.
Features:
For modern home
rice cookers, the smallest single-person model cooks 1 rice cup (180 ml),
whereas large models can cook 10 cups. Commercial models can cook 20 or more
cups. As a possible source of confusion, model specifications and names may
list either cooked or uncooked capacity. Rice roughly doubles in size during
cooking; therefore, a 10 cup (uncooked) rice cooker can produce up to 20 cups
of cooked rice. The prices vary greatly, depending on the capacity, features,
materials used, and the country of origin.
The majority of
modern electric rice cookers are equipped with a stay-warm or keep-warm feature,
which keeps the rice at an optimal temperature for serving without over-cooking
it. Some gas cookers also have electric stay-warm mechanism. However, the
usefulness of this feature degrades over time, a microwave may be more energy
efficient or better suited to reheat rice that will sit longer than four hours.
Some rice
cookers use induction heating, with one or more induction heaters directly
warming the pot. This can improve energy efficiency.
Most modern
rice cookers use aluminium for the inner cooking bowl. There are some models
that use stainless steel instead of aluminium. Various other materials, such as
copper, pure carbon, ceramic, and diamond powder coating, may be used for
higher heat conductivity or better taste.
The
pressure-cooking models can raise the water's boiling point higher, e.g., from
100 °C at 1.0 atm up to about 110 °C at 1.4 atm, which speeds cooking. The
pressure-cooking models can also be used in high altitude areas, where the
boiling temperature is below 100 Celsius. Pressure cookers are also suitable
for cooking brown rice (which contains oils and bran fiber that cook
differently from pure white rice starch). Some pressure rice cookers have a
varying pressure control mechanism (named the "dual-pressure" method)
that creates repeated pressure/release cycles during the cooking.
There also
exist mechanisms to collect and return the boiled over liquid to the inner rice
bowl.
Many cookers now have microprocessor-controlled cooking cycles, which are often used to adjust for rice and
cooking type.
Applications
Rice cookers are typically used for the preparation of plain or
lightly seasoned rice. Each rice cooker model may be optimized to cook a
certain type of rice best. For example, most Japanese rice cookers are
optimized for cooking Japanese rice and may not be the best for other types of
rice[citation needed], although cooking time can be lengthened simply by more
water.
The typical method of cooking long grain rice
is boil-and-strain and/or steaming method. The absorption method used in
Japanese rice cookers will produce slightly different texture and taste,
usually stickier rice.
Brown rice generally needs longer cooking
times than white rice, unless it is broken or flourblasted (which perforates
the bran).
Different varieties of rice need different
cooking times, depending on their grain size, grain shape, and grain
composition. There are three main types of Asian rice: Oryza sativa subsp.
indica, i.e., Indian rice (long grain rice, e.g., basmati rice and Thai jasmine
rice), O. sativa subsp. javanica, i.e., Java rice (large grain rice) and O.
sativa subsp. japonica, i.e., Japanese rice (medium grain rice, e.g., Calrose
rice, short grain rice, e.g., most Japanese rice and risotto rice).
African rice, Oryza glaberrima, is an entirely
separate species, but can be cooked in the same way. Zizania is not even in the
same genus, although it is often called a rice (or "water oats"); it,
too, can also be cooked in a rice cooker.
A
rice cooker can be used to cook many boiled or steamed granular foods, such as
pot barley, bulgar wheat, and dal. Provided the ingredients have similar
cooking times, a rice cooker can cook mixtures such as khichdi. Some rice
cookers can be used as automated couscoussiers, cooking couscous and a stew
simultaneously.
Rice Cooker Rice Cooker,Drum Rice Cooker,Deluxe Rice Cooker,Straight Rice Cooker Guangzhou Taipeng Electrical Appliances Technology CO., LTD. , https://www.taipengelectric.com