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Why emitter is heavily doped and base is lightly dopped working of p-n-p transistor?
Wiki User
∙ 12y ago
Emitter is heavily doped because to provide charge carriers to Base & Collector region, Base and Collectors are lightly doped because to accept those charge carriers.
Wiki User
∙ 12y ago
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Why is it necessary to bias a transistor when it is to be used as an amplifier?
Biasing is necessary in a transistor circuit to keep the transistor working. Without proper biasing, the circuit will fail
What should be the value of capacitor at transistor amplifier circuit input?
at full input, if the transistor is working, the value of capacitor will be 0.
What is the difference between npn and pnp transistor?
In NPN transistor, Base is connected to positive terminal of battery.Now, when current is switched on, Base-Emitter junction (indicated in image) is forward biased, whereas Base-Collector junction is reverse biased.Remember that forward bias narrows depletion region, whereas reverse bias widens depletion region.n-type region(lower one) on emitter side has majority electrons (reason 'n' stands for negative).These electrons move from emitter side to base.Base is thin region, which has holes. When electrons move from emitter to base only a few electrons combine with holes. Whereas others pass from base to collector.In collector the electrons are pulled by positive terminal of battery(right hand side battery). And thus the cycle of current continues to flow.That is whole working of NPN transistor.
How does a transistor work as a switch explain with diagram?
In brief and in the most general terms, a transistor is a 3-terminal semiconductor device capable of changing its resistance in a "controlled" way. It is like the valve (the hose bib) that you open to turn on the water to your hose. The valve allows you to apply a little energy (from your hand) to control lots of energy (the water pressure). That's amplification. Let's peek in on this and make some simple comparisons. A transistor has an emitter, a collector and a base. The emitter and collector could be considered "input and output" terminals in the most basic sense. As for the base, it is the "control terminal" just like the handle on the faucet. By applying a small voltage to the base to "turn on" the device, we can get current to begin flowing. First a little, and then, by turning it on more, a lot. Eventually the device will be "all the way on" and will be allowing maximum current to flow through it. The opposite will be true when we turn the device off. That's it. Oh, but let's take a moment to look at the implications, shall we? Imagine turning on the water really, really fast. Like almost instantly on. Then off the same way. By turning the transistor on and off "instantly" and looking at the result, we'd get "ons" and "offs" from it. That's 1's and 0's there, and it's binary. That's how we can make a digital signal. And this process is exactly at the heart of how the microprocessor in all digital computers works. You probably saw that coming. Let's look at one other thing. You're familiar with sound, which is mechanical energy. It's like a vibrating string on a guitar or the membrane ("skin") on a drum, just to cite a pair of examples. That movement creates harmonic or oscillating motion and the sound. If we want to create the electrical equivalent, we have to open and close that water valve as quickly as the frequency of the vibrations. That's not really possible with the valve, but with the transistor, we can apply a changing voltage to the base as fast as any "regular" mechanical vibration. If a string vibrates at 1000 cycles per second (1000 Hertz), we can change the voltage to the base at that rate. Let's slow the action down. Note that we start turning on the transistor, then we turn it on a bit more, then a bit more. At some point we've reached a "peak" and then we start turning it off, and off a bit more and off a bit more until it's off. The rateat which we do this corresponds to the frequency of the signal being amplified by the transistor. And how far we actually turn the transistor on before turning it back off corresponds to the amplitude of the signal we are working with. The transistor has largely replaced the vacuum tube, which was originally called an electronic valve. Having wandered around in this discussion, you may be able to see why the terminology (which is a bit "old school" now) can still be fairly applied - even to the transistor.
How will you know if the transistor is working or faulty?
Impossible to give a specific answer without more information. Is it a BJT or a FET? Most general answer is you first have to understand the circuit using the transistor and what it's supposed to do. Then, 1. Check that the power supply voltages are correct. 2. Check that the DC biases are correct. 3. Check that the input signal is correct. 4. Check the output. But you have to know in advance what to expect.
What is the working of a transistor?
For proper working of a transistor,the voltage at the base region must be more positive than that of the emitter region.The voltage at the collector region, in turn, must be more positive than that of the base region.when voltage is applied to transistor, the emitter supplies electron,which is pulled by the base from the emitter as it is more positive than the emitter.This movement of electrons from emitter to collector creates as flow of electricity through the transistor.The current passes from the emitter to the collector through the base.Thus, adjustment of voltage in the base region modifies the flow of the current in the transistor by changing the number of electron in the base region. In this way, small changes in the base voltage can cause large changes in the current flowing out of the collector. We have three transistor element, a.)Emitter b.)Base c.)Collector
What is the working of a Darlington amplifier?
it is a combination of two transistors connected in series. the emitter of transistor t1 is connected to the base of transistor t2 . now the total circuit acts as a single transistor. this combination will gives high gain, as the gain is multiplied.
Working of npn transistor?
N-p-n transistor is made by sandwiching thin layer of p-type semiconductor between two layers of n-type semiconductor. It has three terminals, Emitter, Base and collector. The npn transistor has two supplies, one is connected through the emitter base and one through the collector base. The supply is connected such that emitter-base are forward biased and collector base are reverse biased. It means , Base has to be more positive than the emitter and in turn, the collector must be more positive than the base. The current flow in this type of transistor is carried through movement of electrons. Emitter emits electrons which are pulled my the base as it is more positive. these end up in the collector as it is yet more positive. In this way, current flows in the transistor. Transistor can be used as an amplifier, a switch etc.
What is the explanation for the working CE BJT amplifier?
In electronics, a common-emitter amplifier is one of three basic single-stage bipolar-junction-transistor (BJT) amplifier topologies, typically used as a voltage amplifier. In this circuit the base terminal of the transistor serves as the input, the collector is the output, and the emitter is common to both (for example, it may be tied to ground reference or a power supply rail), hence its name.
Relation between current gain and collector current?
That's referred to as, `hfe` in transistor parlance. Essentially, since a transistor is a current operated device, the gain means that for every milliamp in at the base, the gain (times X) will be amplified through the junction of the collector/emitter. For instance, take a transistor with a gain of 30. One milliamp in at the base will allow the transistor to pass 30 milliamps through the collector/emitter junction. Of course, there will also be a resultant voltage drop of 1.2 volts over all. -.6 volts for the base and -.6 volts through the collector/emitter junction. Remember, you're working with a current controlled device, and not a voltage controlled device like an op-amp.
How common emitter amplifire do working?
i dont knw
Internal circuit diagram and working principle of transistor npn sl100?
This mechanism is how a transistor works.
Why is it necessary to bias a transistor when it is to be used as an amplifier?
Biasing is necessary in a transistor circuit to keep the transistor working. Without proper biasing, the circuit will fail
How do you test a transistor is there any meter to test?
You can do simple resistance tests on the various diode junctions. Measure each of the pairs of diode junctions. Collector-emitter, collector-base, base-emitter. Read the resistance of one junction and then read the same junction with the polarity probes switched. One side should read very high resistance, over 1 megohms. And the other should read a moderate resistance, a few hundred thousand ohms. If this is the case for all three junctions, the transistor should be a good working one.
What would happen if the emitter resistor fails to open?
This is an overcurrent condition, correct? The real answer is, "well, it's not SUPPOSED to open!" Which is true--if the emitter resistor opens, the smoke (which, as we all know, is the thing that makes electrical devices work) gets out and the circuit stops working. If you're in an overcurrent condition sufficient to destroy parts and you don't lose the resistor, the transistor being serviced by the emitter resistor is destroyed. Having said that, the circuit should be designed so the bias current is low enough that it won't destroy parts.
What should be the value of capacitor at transistor amplifier circuit input?
at full input, if the transistor is working, the value of capacitor will be 0.
How does a jfet input operational amplifier work?
A: an operational amplifier has two input A+ and a - input feeding to a base of a transistor ideally both diodes are matched with a current source to make them equal so basically they are both balanced or virtually at the same potential increasing one potential to one will inversely effect the other. usually these junctions are transistor base to emitter but it could that one is just a plain diode working on the exponential curve of the diodes
