Connecting a resistance btw the o/p and i/p of the amplifier to increase the i/p impedance is called bootstrapping..
The advantage of the emitter follower is that it has a positive gain of 1.
emitter follower is a type of negative feedback ,
no difference between emiter follower and source 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.
A: When a signal is not amplified but simply taken from an emitter the reason is that the emitter will provide better current capabilities
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".
The advantage of the emitter follower is that it has a positive gain of 1.
emitter follower is a type of negative feedback ,
A: Any transistor of either polarity can be used as an emitter follower, The purpose of an emitter follower is to provide current to the load since it cannot provide any voltage gain
no difference between emiter follower and source 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.
A: When a signal is not amplified but simply taken from an emitter the reason is that the emitter will provide better current capabilities
higher current handling / heat dissipation This is not really true as those are not singular characteristics of darlingtons. The major characteristics of a darlington is high gain, typically ranging from over 100 to 1000. And since there are essentially two transistors in the case of a darlington and the base of a darlington is connected to the base of the first transistor whose emitter is connected to the base of the second (power or output) transistor, the forward voltage drop from the base to the emitter of the darlington is approximately 2 times the forward voltage drop of a single transistor. it is a beta multiplier therefore it has higher emitter current capability and it not a hi gain per say just higher current capability as opposed to a regular transistor. usage is for an emitter follower which has no voltgage gain at all.
The voltage gain of an emitter follower is theoretically 1. In practice, due to losses, it is marginally less than one.
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.
It is not called that.
It is not. You have something confused.