Q. Why CE configuration is widely used in amplifier circuits?
The main ability of an transistor lies in amplifying weak signals. The transistor cannot alone perform this function; we have to connect some passive components and a biasing battery. Such a circuit is called an amplifier. The main utility of a transistor lies in amplifying a circuit. An amplifier is something which is capable of amplifying. A CE configuration is popularly used for amplification, because its input resistance is about 1 and the output resistance about 10 k?. A transistor in the CE configuration makes a much better amplifier because it has got high current gain, voltage gain and power gain. To obtain proper amplification cascading of transistors can be done. CE configuration is best suited for cascaded amplifiers. If we consider a two stage cascaded amplifier then the first stage works as a voltage source for the second source. The input resistance of the second stage serves as a load resistance for the first source. The output resistance of the first stage is the internal resistance of the voltage source. The internal resistance of the source must be low compared to load resistance .Again, the second amplifier stage will deliver more power to the the load only if its output resistance is low. Thus we find that a good amplifier stage is one which has high input resistance and low output resistance.