Question

I think I have a little bit of understanding of input impedance impedance, but please check my understanding, and also explain physically what output impedance and reactance is AND EXPLAIN YOUR TERMINOLOGY or use basic af terminology:

Input impedance describes (I think) a voltage source, or something that produces an output voltage, and its impedance within it's own circuitry. In other words, say I have a function generator, something supposed to output voltage, and the input impedance would be the impedance within the confines of its own circuitry, but not internal to it's battery/power supply.

I don't know if that makes sense or not, but if I'm on the right track, please elaborate just a little more in the most basic, easy to understand language (please avoid using certain words, like "network," or things of this nature, without explaining what you mean by them, and please don't just go google my questions, because I've already done that, which is why I'm here).

Still don't know what output impedance is. Or reactance (I think it's resistance, but for nonlinear circuits, such as LRC, RC, etc.).

Answer 1

In simple words, impedance means something that act as obstacle (or oppose).

INPUT IMPEDANCE   is basically the measure of impedance of the circuit (LCR, RC, LC or any other) at the input terminals of that circuit.

while, OUTPUT IMPEDANCE , is the measure of impedance at the output terminals of the circuit.

NOW, impedance is basically a measure of the opposition to the flow of an a.c. (alternating current) in a circuit.

It is generally defined as the ratio of voltage to the current flowing in the circuit.

For input impedance , it is the ratio of input voltage across the input terminals to the input current flowing through the input terminals of the circuit while output impedance, is the ratio of output voltage across the output terminals to the output current flowing through the output terminals of the circuit.

so don't confuse about input and output impedance.

Both input and output impedance are confines within the circuits and it mainly depends upon the capacitance of the capacitor , inductance of an inductor, resistance of a resistor in the circuit.

Generally we prefer high input impedance over low input impedance .Thia is because ,there will be no voltage drop across the source impedance when input impedance is assumed to be infinity.

Reactance is denoted X. Reactance is expressed in imaginary number ohms.It is observed for AC, but not for DC sources.

Reactance is the resistance offered to the ac currents by inductors and capacitors only.

For capacitors X=1/(2πfC); where f is the frequency,C is the capacitance.

For inductors X= 2πfL; where f is the frequency,:L is the inductance.

Impedance is the sum of the resistance and reactance of a circuit

denoted by Z=R+jX (for primarily inductive circuits) or Z=R - jX (for primarily capacitive circuits).

where j=√(-1).

Hope , you understand .