emitter follower is a type of negative feedback ,
negative feedback
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.
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.
It can be used as a feedback and to ground unwanted signals and frequencies
for stability
there are four types of feedback connetion. the one used is that which amplifies your input (Positive 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
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.
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.
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.
the same as the base minus Vbe drop. used for more power transfer
It can be used as a feedback and to ground unwanted signals and frequencies
constructive feedback
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.
In a Voltage Shunt feedback Amplifier, the feedback signal voltage is given to base of transistor in shunt through a feedback resistor.This Shunt connection decreases the input input impedance and voltage feedback decreases the output impedance. In this amplifier input is current and output is voltage. Thus Transresistance is stabilized.Input and Output impedances are reduced by a factor of 'D'(desensitivity factor). Advantages: 1)Gain independent of device parameters. 2)Bandwidth increases. 3)Noise and non-Linear distortion decrease. 4)Prevents Loading effect. 5)Acts as good source for the next stage.
Negative Feedback Loops
Roller follower
A: The ratio of emitter/collector resistance is the gain. by adding a capacitor on the emitter the AC parameters will shift as a function of frequency