The correct answer is: A. high
A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor’s terminals changes the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.
The input impedance of a transistor is high. This means that the transistor draws very little current from the source of the input signal. This is important because it allows the transistor to be used to amplify weak signals without distorting them.
The other options are incorrect because they do not accurately describe the input impedance of a transistor. Option B, “low,” is incorrect because the input impedance of a transistor is actually quite high. Option C, “very high,” is also incorrect because it is an exaggeration. Option D, “almost zero,” is incorrect because it is not accurate.
In conclusion, the input impedance of a transistor is high. This means that the transistor draws very little current from the source of the input signal. This is important because it allows the transistor to be used to amplify weak signals without distorting them.