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What is the difference between a CB amplifier and CE and emitter-follower?
I think you mean a common emitter amplifier, which is an amplifier of voltage. Emitter-follower or common collector amplifiers are used to match impedances, or to amplify power or current. The emitter-follower is a type of common emitter circuit that has a resistor between the emitter and ground. The output signal is taken from the point between the emitter and its resistor.
What is the effect of no emitter resistance on common emitter amplifier?
Limit current through emitter, Often the resistance is the load itself. So the restatnce limits current on what otherwise would act as a voltage follower.
Why emitter follower is used in circuits?
The (Class C, Common Collector) Emitter Follower is used to amplify the available current from a voltage driving circuit that might be disturbed by the load impedance. If the actual voltage value is important, the emitter follower is often teamed up with an opamp which sets the emitter voltage based on the input voltage.
Why emitter follower is called so?
Because of the geometry of the common collector configuration, changes in base voltage appear at the emitter. Said another way, what happens at the base pretty much happens at the emitter, and the emitter can be said to "mirror" or "follow" the base. The emitter is a follower of the base, and the name emitter follower appeared and was used.
Why npn transistor is called emitter follower?
because one of the terminals is common for for both i/p and o/p
Capacitor from emitter to ground in common emitter circuit is called?
The capacitor is called a bypass capacitor , it provides a low impedence path for AC emitter current to groun.
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.
Why more current amplification in common emitter?
A bipolar transistor can be used in different configurations in linear electronic design. Most well known is the common emitter CE configuration with a base current as input signal resulting in a collector signal multiplied by the current gain factor. The second configuration is known as the emitter follower or common collector configuration. Here the input signal is in the form of a voltage between the base and the common connection. The output signal is found in the form of a voltage at the emitter with a relative low output impedance. The voltage swing at the input is almost as large at the output where the input impedance equals the product of the current gain factor and the emitter resistance. The third configuration is known as common base CB. Here the input current at the emitter almost equals the output current at the collector. The current gain is nearly equal to 1.
What is darlington emitter follower?
A darlington emitter follower is two transistors operating as one. Both collectors are tied together. The emitter of the first is connected to the base of the second. The darlington exhibits very high gain. If hFe, for instance, on each transistor was nominally 100, the effective hFe would be nominally 100 squared, or 10000. The emitter follower is a common collector configuration where the emitter tracks the base, offset by the base-emitter forward junction voltage. In a darlington, there are two junctions in series, so the effective junction voltage is about 1.4V. Voltage gain of the darlington, like any emitter follower, is one, or unity. Current gain, however, is limited only by the power supply, the transistor, and effective hFe. In the darlington configuration, current gain is effectively considered to be large enough to be thought of as "infinite".
What are three configurations that can be used with FET devices?
configurations of Common-source (CS), Common-drain (CD) or Source-follower (SF) and the Common-gate (CG) available for most FET devices. These three JFET amplifier configurations correspond to the common-emitter, emitter-follower and the common-base configurations using bipolar transistors.
Why output of common emitter amplifier is inverted?
In a common emitter amplifier, the base-emitter current causes a corresponding collector-emitter current, in the ratio of hFe (beta gain) or collector resistance over emitter resistance, which ever is less. Since this ratio is usually greater than one, the differential collector current is greater than the differential base current. This results in amplification of the base signal. As you increase the base-emitter current, the collector-emitter current also increases. This results in the collector being pulled towards the emitter, with the result that the differential collector voltage decreases. This results in inversion of the base signal.
What are the disadvantages of using common emitter amplifier?
Disadvantages of CE amplifier:1. It has a high output resistance.2. It responds poorly to high frequencies.3. It has high thermal instabilities.4. It's voltage gain is very unstable.
