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What is a diode?
A diode is a one way valve for electricity. It will allow current to flow in one direction but not in the opposite direction.
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diode:= di+ iode di means two,and iode means terminal,,,, diode is two terminal device i.e anode and cathode
The most common function of a diode is to allow an electric current to pass in one direction (called the forward biased condition) and to block the current in the opposi…te direction (the reverse biased condition).
Diode is a two terminal device (di- means "two"). Simply put, it acts as a one-way valve for electrons. Conventional current can flow from the anode to the cathode, but not in… the other direction. If an intrinsic semiconductor is doped with a pentavalent or trivalent impurities you get a diode. A diode is formed when a region of N-type semiconductor touches a section of P-type. In the N-type region electrons are the majority carriers and in the P-type electron "holes" are the majority carriers. If forward-biased (applying a positive voltage to the P region and a negative voltage to the N region), the depletion region of the diode decreases. The electrons on the N side are repelled and they move towards the P side thus reducing the size of the depletion layer. If reverse-biased, the depletion region increases because the electrons are attracted towards the positive voltage and the holes are attracted towards the negative voltage, and hence the current gets reduced and the current flowing will be very small, on the order of microamps. This is called as reverse saturation current. Although an ideal diode acts like a switch and it is a useful approximation, real diodes are not ideal: a real diode has other properties that are sometimes useful and sometimes a drawback. For example, a real diode requires some forward voltage to turn on, usually around 0.3-0.6 volts, depending on the type. Also a reverse-biased diode can act like a variable capacitor, which can be used to make voltage controlled oscillators and tuning filters. Reverse-biased diodes (voltage applied so they turn off) will eventually break down if enough reverse voltage is applied, and allow current to flow. This is used to make Zener diodes that breakdown at a specific voltage, useful in voltage regulation.
Answer A vacuum diode is an electron valve that supports current flow through it in only one direction. It is composed of two electrical "parts" or elements and t…he evacuated glass envelope. Additionally, there is usually a heater, a coil of special alloy wire that can be driven to red heat by a modest application of voltage. (A vacuum diode without a heater would be a cold cathode diode.) The heater is coiled inside a cylindrical element called the cathode. The cathode is composed of a special alloy, or, more properly is coated with an alloy, that has high thermal emission characteristics. That means that if it's heated sufficiently, electrons actually leave the metallic crystal structure of the metal (boil off) and hang around outside in the space nearby forming what is called a space charge. When we built the tube, we pumped all the air out, sealed the glass, and then fired a "getter" inside the tube to chemically bind the remaining bit of gas that was there. The tube really is highly evacuated. That's important because we don't want all those light weight electrons bumping into gas atoms and molecules when they are hanging around in the space charge, and especially when transiting the gap between the cathode and the other element inside, the anode or plate. If a voltage is applied across the cathode and plate, and the plate is negative, no current will flow in the tube. Electrons flow from negative to positive, but, darn it, they can't leave the plate to go to the cathode. That's called reverse biased. It's hooked up "backwards" like that. But if the cathode is connected to negative and the positive connected to the plate, electrons that were in the space charge will be driven away from the cathode and attracted to the plate. Current will flow in this direction. That's forward bias. There isn't a lot of internal resistance when the diode is forward biased, either. It conducts really well. The vacuum diode can be used to rectify an AC voltage and turn it into DC. In that application, it permits current flow during half the AC cycle (when it's forward biased), and does not allow it in the other (reverse biased) half. There aren't a lot of vacuum tubes around like back in the day. Modern electronics has seen innovations that have driven the vacuum diode away. Hey, wait a minute! They're still here! They sneaked back! But they're here in disguise!! I'll betcha that you've got one in your house! Yeah! You got a microwave oven at home? The heart of a microwave oven is a (specialized) vacuum diode that sits inside a magnetic field. It's called a magnetron, and it's the microwave generating device inside the appliance. Betcha didn't know that. The way the magnetron works is..., hey, wait. That's another question.
Electronic parts which is designed to make several type of electronic circuits. Contains semi-conductors, mainly Si(Silicon) and Ge(Germanium).
A: A diode array that will conduct if anyone of them are hi as in gates
Today, all diodes are semiconductor diodes. However, the first diodes were piles of washers of different metals that together made a diode, and specially constructed vacuum tu…bes. There may still be markets for other types of diodes in very high voltage circuits, but you or i are unlikely to come in contact with them.
At the time of their invention, such devices were known as rectifiers. In 1919, the year tetrodes were invented, William Henry Eccles coined the term diode from the Greek root…s di (from δί), meaning "two", and ode (from ὁδός), meaning "path".
It's a diode that is used to limit a voltage to some desired value. Importantly, it's used to limit a transient voltage or an alternative voltage. The simplest e…xample is that diode placed across a relay's inductive coil. As current is cut off through the coil, a large induced voltage appears that can cause damage to the circuit. A diode can be placed in circuit to catch/damp the induced voltage.
Answer A diode is used to control current flow in a circuit A diode has a very high resistance to current flow in one direction and a very low resistance to cu…rrent flow in the opposite direction
A diode is a semiconductor device that passes current in one direction only. Sometimes, in the case of zener diodes, it conducts in both directions, but at a different voltage… in the reverse direction. Diodes can be used for...Rectifiers, to convert AC to DCAuctioneering/Isolation, where one of two sources can supply the load, but those sources must not interfere with each otherVoltage reference, particularly for zenersClipping, in order to narrow the voltage range of a signalDetection, in order to demodulate a signal from a carrierMixing, in order to mix an RF signal with a Local Oscillator in the superhetrodyne receiver There are other uses - this list is only a sample
A diode is a semiconductor meaning it will conduct from anode to cathode if the anode is held positive. Reversing the polarity Will in effect block current flow.
A Gunn diode, also known as a transferred electron device (TED), is a form of diode used in high-frequency electronics. It is somewhat unusual in that it consists only of N-do…ped semiconductor material, whereas most diodes consist of both P and N-doped regions. In the Gunn diode, three regions exist: two of them are heavily N-doped on each terminal, with a thin layer of lightly doped material in between. When a voltage is applied to the device, the electrical gradient will be largest across the thin middle layer. Conduction will take place as in any conductive material with current being proportional to the applied voltage. Eventually, at higher field values, the conductive properties of the middle layer will be altered, increasing its resistivity and reducing the gradient across it, preventing further conduction and current actually starts to fall down. In practice, this means a Gunn diode has a region of negative differential resistance.
Diode is a pn junction device which conducts (current flow)in forward direction. Zener diode is a device in which current flows in forward direction as well as in reverse di…rection.For a Zener diode,current flows in reverse direction if the voltage is larger than the breakdown voltage,where the breakdown voltage is the minimum reverse voltage to make the diode conduct in reverse.