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Why are silicon diodes not suited for low voltage rectifiers?
Silicon diodes ARE used in reverse bias. This is the mode in which they do not conduct, which is the principal role of a diode. When forward biased, a silicon diode will conduct but has a voltage drop of around 0.6v so is not useful for rectifying small voltages (unless used as a perfect diode with an op amp).
What is the role of a technical support engineer?
The role of a technical support engineer is to plan analyze the program of the each profile plan, as per standard engineering requirements, specification of the project.
How long do laser pointers last?
The lifespan of a laser pointer typically ranges from 5,000 to 10,000 hours of use, depending on the quality of the device and the type of laser used. Factors such as battery life, usage frequency, and environmental conditions can also affect longevity. Regular maintenance and proper handling can help maximize the lifespan of a laser pointer. Ultimately, the durability of the components, especially the diode, plays a crucial role in determining how long it will last.
What is the role of mechanical engineering in national development?
The role of mechanical engineers in the national development.
What is the principle used in light emitting diode?
A diode is the simplest sort of semiconductor device. Broadly speaking, a semiconductor is a material with a varying ability to conduct electrical current. Most semiconductors are made of a poor conductor that has had impurities (atoms of another material) added to it. The process of adding impurities is called doping. In the case of LEDs, the conductor material is typically aluminum-gallium-arsenide (AlGaAs). In pure aluminum-gallium-arsenide, all of the atoms bond perfectly to their neighbors, leaving no free electrons (negatively-charged particles) to conduct electric current. In doped material, additional atoms change the balance, either adding free electrons or creating holes where electrons can go. Either of these additions make the material more conductive. A semiconductor with extra electrons is called N-type material, since it has extra negatively-charged particles. In N-type material, free electrons move from a negatively-charged area to a positively charged area. A semiconductor with extra holes is called P-type material, since it effectively has extra positively-charged particles. Electrons can jump from hole to hole, moving from a negatively-charged area to a positively-charged area. As a result, the holes themselves appear to move from a positively-charged area to a negatively-charged area. A diode comprises a section of N-type material bonded to a section of P-type material, with electrodes on each end. This arrangement conducts electricity in only one direction. When no voltage is applied to the diode, electrons from the N-type material fill holes from the P-type material along the junction between the layers, forming a depletion zone. In a depletion zone, the semiconductor material is returned to its original insulating state -- all of the holes are filled, so there are no free electrons or empty spaces for electrons, and charge can't flow. At the junction, free electrons from the N-type material fill holes from the P-type material. This creates an insulating layer in the middle of the diode called the depletion zone. To get rid of the depletion zone, you have to get electrons moving from the N-type area to the P-type area and holes moving in the reverse direction. To do this, you connect the N-type side of the diode to the negative end of a circuit and the P-type side to the positive end. The free electrons in the N-type material are repelled by the negative electrode and drawn to the positive electrode. The holes in the P-type material move the other way. When the voltage difference between the electrodes is high enough, the electrons in the depletion zone are boosted out of their holes and begin moving freely again. The depletion zone disappears, and charge moves across the diode. When the negative end of the circuit is hooked up to the N-type layer and the positive end is hooked up to P-type layer, electrons and holes start moving and the depletion zone disappears. If you try to run current the other way, with the P-type side connected to the negative end of the circuit and the N-type side connected to the positive end, current will not flow. The negative electrons in the N-type material are attracted to the positive electrode. The positive holes in the P-type material are attracted to the negative electrode. No current flows across the junction because the holes and the electrons are each moving in the wrong direction. The depletion zone increases. (See How Semiconductors Work for more information on the entire process.) When the positive end of the circuit is hooked up to the N-type layer and the negative end is hooked up to the P-type layer, free electrons collect on one end of the diode and holes collect on the other. The depletion zone gets bigger. The interaction between electrons and holes in this setup has an interesting side effect -- it generates light! In the next section, we'll find out exactly why this is. How Can a Diode Produce Light? Light is a form of energy that can be released by an atom. It is made up of many small particle-like packets that have energy and momentum but no mass. These particles, called photons, are the most basic units of light. Photons are released as a result of moving electrons. In an atom, electrons move in orbitals around the nucleus. Electrons in different orbitals have different amounts of energy. Generally speaking, electrons with greater energy move in orbitals farther away from the nucleus. For an electron to jump from a lower orbital to a higher orbital, something has to boost its energy level. Conversely, an electron releases energy when it drops from a higher orbital to a lower one. This energy is released in the form of a photon. A greater energy drop releases a higher-energy photon, which is characterized by a higher frequency. (Check out How Light Works for a full explanation.) As we saw in the last section, free electrons moving across a diode can fall into empty holes from the P-type layer. This involves a drop from the conduction band to a lower orbital, so the electrons release energy in the form of photons. This happens in any diode, but you can only see the photons when the diode is composed of certain material. The atoms in a standard silicon diode, for example, are arranged in such a way that the electron drops a relatively short distance. As a result, the photon's frequency is so low that it is invisible to the human eye -- it is in the infrared portion of the light spectrum. This isn't necessarily a bad thing, of course: Infrared LEDs are ideal for remote controls, among other things. [全屏欣赏] Visible light-emitting diodes (VLEDs), such as the ones that light up numbers in a digital clock, are made of materials characterized by a wider gap between the conduction band and the lower orbitals. The size of the gap determines the frequency of the photon -- in other words, it determines the color of the light. While all diodes release light, most don't do it very effectively. In an ordinary diode, the semiconductor material itself ends up absorbing a lot of the light energy. LEDs are specially constructed to release a large number of photons outward. Additionally, they are housed in a plastic bulb that concentrates the light in a particular direction. As you can see in the diagram, most of the light from the diode bounces off the sides of the bulb, traveling on through the rounded end. LEDs have several advantages over conventional incandescent lamps. For one thing, they don't have a filament that will burn out, so they last much longer. Additionally, their small plastic bulb makes them a lot more durable. They also fit more easily into modern electronic circuits. But the main advantage is efficiency. In conventional incandescent bulbs, the light-production process involves generating a lot of heat (the filament must be warmed). This is completely wasted energy, unless you're using the lamp as a heater, because a huge portion of the available electricity isn't going toward producing visible light. LEDs generate very little heat, relatively speaking. A much higher percentage of the electrical power is going directly to generating light, which cuts down on the electricity demands considerably. Up until recently, LEDs were too expensive to use for most lighting applications because they're built around advanced semiconductor material. The price of semiconductor devices has plummeted over the past decade, however, making LEDs a more cost-effective lighting option for a wide range of situations. While they may be more expensive than incandescent lights up front, their lower cost in the long run can make them a better buy. In the future, they will play an even bigger role in the world of technology.
What is another name for route 40 which goes through wheeling?
Another name for Route 40 that goes through Wheeling is the National Road. This historic route was the first major highway in the United States built by the federal government and played a significant role in westward expansion. Today, it is recognized for its scenic views and historical landmarks along its path.
Humanism denies the role of determinism but elevates the role of?
Free Will
Why was wheeling nicknamed ''nail city''?
Wheeling, West Virginia, earned the nickname "Nail City" due to its historical significance as a major center for nail manufacturing during the 19th century. The city was home to several nail factories that produced a large portion of the nails used in construction across the United States. This nickname reflects Wheeling's industrial heritage and its contributions to the growth of the American economy during that era. The nail industry played a crucial role in shaping the local economy and employment landscape.
Why are silicon diodes not suited for low voltage rectifiers?
Silicon diodes ARE used in reverse bias. This is the mode in which they do not conduct, which is the principal role of a diode. When forward biased, a silicon diode will conduct but has a voltage drop of around 0.6v so is not useful for rectifying small voltages (unless used as a perfect diode with an op amp).
What is the role of free enterprise?
TRADE
What is the role of graphics in the free enterprise system?
NO
What is role in pregnancy in banana?
free motion
Role of profit in a free market economy?
the role is...ehhh i dont know. sorry :(
What is the role of an individual within the free enterprise system as a producer consumer and a citizen?
What is the role of an individual within the free enterprise system as a producer consumer and a citizen?"
What is a drug free role model?
A role model is someone people can admire who leads through example. A drug free role model is someone who teaches others not to be influenced by drugs by not using drugs his or her self.
What is the role of Free Radicals in Cardiovascular diseases?
there is none
What is the role of households in a free market economy?
households are important role in free market economy. they only called as customers and consumers in the free market economy so they involved goods purchase and selling activities..
