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Why a transistor has low input impedance and high output impedance?
The input impedance is much higher than its output impedance so that a signal source does not have to supply as much power to the input. This can be seen from the fact that the base current is on the order of 100 times (β) less than the emitter current.
Why is a resistor positioned before the transistor?
The resistors are used as a means of generating voltage drops and thereby pulling the transistor into the desired operating region. because you need to limit the current to semiconductor terminals. otherwise, the transistors will be damaged.
Is the input resistance of a transistor linear or non linear?
If it is a bipolar transistor (BJT), there is no actual input resistance. The current vs. voltage relationship of the Base terminal is not linear, so there is no specific number. The current that flows depends on the voltage provided (in a non-linear manner).
Why is resistance in reference to a transistor important?
Since only a small amount of base current is needed to vary the transistor’s resistance between a very high and a very low value, the output voltage can be many times larger than the input voltage. Hence, the transistor acts as an amplifier. Unfortunately, a transistor has some issues.
What is the internal resistance of a battery?
If you take an ideal battery and draw some current from it, ideally the voltage will not change.We say that an ideal battery has an internal resistance of zero ohms, and that is because if you put current into or take current out of an ideal battery the voltage will not change.
The closed-loop input resistance is effectively ( Ri ‖ Rf )/ (1 + GH ). The effect of negative feedback on output resistance can be analyzed by representing the output as a Thévenin equivalent voltage source with internal voltage of v and open-loop output resistance of Ro. An output voltage of vo is produced by a current io applied to the output.