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Common Collector Amplifier Common Collector Amplifiers produce an output voltage across its emitter load which is in-phase with the input signal The  Common Collector Amplifier  is another type of bipolar junction transistor, (BJT) configuration where the input signal is applied to the base terminal and the output signal taken from the emitter terminal. Thus the collector terminal is common to both the input and output circuits. This type of configuration is called Common Collector, (CC) because the collector terminal is effectively “grounded” or “earthed” through the power supply. In many ways the common collector configuration (CC) is the reverse of the common emitter (CE) configuration as the connected load resistor is changed from the collector terminal for R C  to the emitter terminal for R E . The common collector or grounded collector configuration is commonly used where a high impedance input source needs to be connected to a low impedance output l...

Class AB Amplifier Class AB amplifier output stage combines the advantages of the Class A amplifier and the Class B amplifier producing a better amplifier design The purpose of any amplifier is to produce an output which follows the characteristics of the input signal but is sufficiently large enough to supply the needs of the load connected to it. We have seen that the power output of an amplifier is the product of the voltage and current, (P = V*I) applied to the load, while the power input is the product of the DC voltage and current taken from the power supply. Although the amplification of a Class A amplifier, (where the output transistor conducts 100% of the time) can be high, the efficiency of the conversion from the DC power supply to an AC power output is generally poor at less than 50%. However if we modify the Class A amplifier circuit to operate in Class B mode, (where each transistor conducts for only 50% of the time) the collector current flows in each tra...

MOSFET Amplifier MOSFET Amplifier uses a metal-oxide silicon transistor connected in the common source configuration In our previous tutorial about FET amplifiers, we saw that simple single stage amplifiers can be made using junction field effect transistors, or JFET’s. But there are other types of field effect transistors available which can be used to construct and amplifier, and in this tutorial we will look at the MOSFET Amplifier. Metal Oxide Semiconductor Field Effect Transistor, or MOSFET for short, is an excellent choice for small signal linear amplifiers as their input impedance is extremely high making them easy to bias. But for a mosfet to produce linear amplification, it has to operate in its saturation region, unlike the Bipolar Junction Transistor. But just like the BJT, it too needs to be biased around a centrally fixed Q-point. A Typical MOSFET Transistor MOSFETS conduct through a conductive region or path called “the channel”. We can make this c...