A: NO it is not fixed it depends on the load line
Common-emitter gives more voltage gain because a common-collector amplifier has a voltage gain of 1. But a common-collector can have a power gain because the input impedance is much more than the output impedance.
common-emitter
emitter collects output current produced in resister Wrong. An emitter in a semiconductor emits majority current carriers (electrons or holes) into the junction between it and the base..
The voltage drop across the emitter-collector junction develops the output signal with the help of a resistor or two in series. The output is 'seen' at the collector.
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.
Common-emitter gives more voltage gain because a common-collector amplifier has a voltage gain of 1. But a common-collector can have a power gain because the input impedance is much more than the output impedance.
because it has high input impedance and low output impedance
bcause amplification factor beta is usually ranges from 20-500 hence this configuration gives appericiable current gain as well as voltage gain at its output on the other hand in the Common Collector configuration has very high input resistance(~750 kilo ohm) & very low output resistance(~25 ohm) so the voltage gain is always less than one & its most important application is for impedance matching for drivingh from low impedance load to high impedance source
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.
The quantity of specific information included in the question is exceeded only bythe quantity of vital, relevant information that's never mentioned.Are you talking vacuum-tube or transistor amplifier ? What's the configuration of theamplifier, i.e., which terminal of the active device is 'common' to input and output ?And where is the bypass capacitor in the circuit ?I'll take a wild stab and assume that you have a common-emitter amplifier, with thecapacitor bypassing the bias resistor in the emitter branch. If that's the case, thenthe resistor is supposed to be there only to set the DC Q-point, but every effect itcould have on small-signal performance would be an effect that you don't want ...it would increase the output impedance, and any impedance common to input andoutput always reduces the gain.So one of the effects of the bypass capacitor is to reduce the output impedanceof the stage.(If Dingobot comes along now and flags this for gibberish, that'll be my first cluethat after all these years, I don't actually remember this stuff too well.)
common-emitter
The output impedance of a common source amplifier circuit is typically high. This is because the common source amplifier uses a resistor to provide biasing, which results in a high output impedance. However, this can be mitigated by using a current source instead of a resistor for biasing.
The output of a common emitter stage is inverted, it is not out of phase.
emitter collects output current produced in resister Wrong. An emitter in a semiconductor emits majority current carriers (electrons or holes) into the junction between it and the base..
The voltage drop across the emitter-collector junction develops the output signal with the help of a resistor or two in series. The output is 'seen' at the collector.
common emitter
A common emitter BJT transistor has the emitter ground. So u measure input voltage at base with respect to the ground, i.e; emitter and also u measure the output voltage at collector with respect to the ground, i.e; emitter. Hence, the emitter is common and thus the name.