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A NPN transistor connected in common base mode has a current gain of 0.98 if it is now connected in common emitter mode what is the current gain?
Wiki User
∙ 13y ago
The current gain in CE mode called as beta (ß)
Tha current gain in CB mode called as alpha (A)
ß= A/(1-A)
=0.98/(1-0.98)
=49
the current gain is 49 in CE mode
Wiki User
∙ 13y ago
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In a common emitter transistor the primary purpose of a resistor connected to the emitter is to?
The emitter resistor in a common emitter configuration provides negative feedback to the transistor, reducing both its voltage gain and distortion.
How does a transistor amplify in a common emitter configuration?
The base is excited by a very low current. That turns the transistor on so that a higher amount of current flow comes out.
Why is collector current increased slowly with the increase of collector to emitter voltage of a common emitter?
The percentage of doping in emitter is higher than collector region.hence large current is flow to emitter than collector.
Transistor as an amplifier common emitter configuration explanation using kirchhof's law?
Kirchoff's current law states that the current in every point in a series circuit is the same. In the case of a transistor in common emitter configuration, you can take advantage of that fact and state that the collector current is equal to the emitter current. The truth is somewhat different, because the gain of the transistor is not infinity, so the base current must be added to the emitter current. With a reasonably high gain, however, you can ignore the base current. Consider that the emitter voltage is related to the base voltage by the forward drop of the base-emitter junction, about 0.7 volts, and the collector and emitter currents are the same. Now look at the collector and emitter resistors. If the currents are the same, and the voltage across the emitter resistor is known, then you know the voltage across the collector resistor as well. This is an application of both Kirchoff's and Ohm's laws. The gain, then, of this amplifer is collector resistance divided by emitter resistance. It is an inverting amplier in this configuration. In some configurations, the emitter resistor is zero ohms. This does not mean the gain is infinity - it now means that the gain is limited by the gain of the transistor, which it is anyway - the emitter resistor is used to stabilize the gain and reduce dependency on individual transistor gains, which do vary.
Characteristic of pnp transistor in common emitter mode precautino and sources of error?
pnp transister in common emitter mode
In a common emitter transistor the primary purpose of a resistor connected to the emitter is to?
The emitter resistor in a common emitter configuration provides negative feedback to the transistor, reducing both its voltage gain and distortion.
What is the difference between common base emitter transistor and common base transistor?
Common base transistor if the emitter is open current Ie=0 but a small collector current thus exist.this current is reversed biased collector to the base voltage it is represented by Icbo while common emitter is d base terminal is open circuit and the base junction is reversed biased current Icbo flow from the tcollector to the emitter in the external circuit this current is called leakage current.
What if base current is zero in a transistor used as an amplifier with common emitter configuration?
output current is zero
How does a transistor amplify in a common emitter configuration?
The base is excited by a very low current. That turns the transistor on so that a higher amount of current flow comes out.
Why base in grounded in common emitter transistor as amplifier?
With a common emitter amplifier it's the emitter that is usually grounded.
What is the alpha beta teta of a bipolar junction transistor?
alpha is the common base current gain = Ic/Ie.beta is the common emitter current gain = Ic/Ib.
How transister work as amplifier?
A transistor works as am amplifier by virtue of the fact that you can control the current in one path with a smaller current in another path. In a typical class A (common emitter) configuration, a certain current from base to emitter will create a corresponding current from collector to emitter. Increasing or decreasing the base-emitter current will cause a corresponding increase or decrease in the collector-emitter current, by a ratio that is defined as hFe, or beta-gain. Of course, this means that you have to properly bias the transistor, and understand the nature of hFe. You can operate a transistor in cutoff mode or saturated mode if you exceed the hFe limits. Within the limits, a properly biased transistor exhibits a (generally) linear operation.
What is the input current for common collector?
from the name itself the common collector has its collector terminal in common with both the input and output circuits of a transistor and the base current is chosen as the input current and the output current is the emitter current
Difference between cascode and cascade amplifier?
cascade: the output of one amplifier stage is connected to the input of another amplifier stages, it's also connected in series. cascode: it said to be cascode, when it has one transistor on the top of another where a common emitter transistor drives a common base transistor.
Why is collector current increased slowly with the increase of collector to emitter voltage of a common emitter?
The percentage of doping in emitter is higher than collector region.hence large current is flow to emitter than collector.
Transistor as an amplifier common emitter configuration explanation using kirchhof's law?
Kirchoff's current law states that the current in every point in a series circuit is the same. In the case of a transistor in common emitter configuration, you can take advantage of that fact and state that the collector current is equal to the emitter current. The truth is somewhat different, because the gain of the transistor is not infinity, so the base current must be added to the emitter current. With a reasonably high gain, however, you can ignore the base current. Consider that the emitter voltage is related to the base voltage by the forward drop of the base-emitter junction, about 0.7 volts, and the collector and emitter currents are the same. Now look at the collector and emitter resistors. If the currents are the same, and the voltage across the emitter resistor is known, then you know the voltage across the collector resistor as well. This is an application of both Kirchoff's and Ohm's laws. The gain, then, of this amplifer is collector resistance divided by emitter resistance. It is an inverting amplier in this configuration. In some configurations, the emitter resistor is zero ohms. This does not mean the gain is infinity - it now means that the gain is limited by the gain of the transistor, which it is anyway - the emitter resistor is used to stabilize the gain and reduce dependency on individual transistor gains, which do vary.
Characteristic of pnp transistor in common emitter mode precautino and sources of error?
pnp transister in common emitter mode
