The difference between resistance and impedance

In circuits with resistors, inductors, and capacitors, the blocking effect on the AC is called impedance.

The impedance is usually represented by Z. The impedance consists of resistance, inductive reactance and capacitive reactance, but not the three are simply added. The unit of impedance is Ω .

 In direct current, the effect of an object on current obstruction is called resistance. All materials in the world have resistance, but the difference in resistance value. Substances with low electrical resistance are called good conductors, such as metals; materials with high electrical resistance are called insulators, such as wood and plastic. There is also a conductor between the two called a semiconductor, and a superconductor is a substance with a resistance value close to zero.

 However, in the field of alternating current, in addition to the resistance will block the current, the capacitance and inductance will also hinder the flow of current. This effect is called reactance, which means resisting the action of current. The reactances of capacitors and inductors are called capacitive reactance and inductive reactance, respectively, referred to as capacitive reactance and inductive reactance. Their unit of measurement is ohmic like the resistance, and the value of the value is related to the frequency of the alternating current. The higher the frequency, the smaller the capacitive reactance is, and the higher the frequency, the larger the capacitive reactance and the smaller the inductive reactance.

In addition, the capacitive reactance and the inductive reactance also have a phase angle problem, and have a vector relationship, so it is said that the impedance is the sum of the resistance and the reactance in the vector. For a particular circuit, the impedance is not constant, but varies with frequency. In a series circuit of resistors, inductors, and capacitors, the impedance of the circuit is generally greater than the resistance. That is, the impedance is reduced to a minimum. In an inductive and capacitive parallel circuit, the impedance increases to a maximum value during resonance, which is the opposite of a series circuit.

Resistance Definition: The resistance of a conductor to current is called the resistance of a conductor.