# Passive Components in AC Circuits

Passive components are circuit devices that can only reduce and increase the electrical power applied to them.

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Electrical and electronic circuits consist of connecting many different components to create a full and closed circuit.The three main passive components used in any circuit are: Resistance, Capacitor and Inductor.All three of these passive components have something in common, which limits the flow of electric current through a circuit in very different ways.

The electric current can pass through one circuit in one of two ways.If it flows only in one direction, it is classified as direct current (DC).If the electric current changes back and forth in both directions, it is classified as alternating current (AC).Although they offer an impedance within a circuit, passive components in AC circuits behave very differently from those in DC circuits.

Passive components consume electrical energy and therefore cannot increase or strengthen the power of any electrical signal applied to them, since they are passive and therefore will always have less than one gain.The passive components used in electrical and electronic circuits can be connected in infinite numbers with the operation of these circuits, depending on the interaction between their different electrical properties, as shown below.

### Passive Components in AC Circuits

Where: R resistance is C capacitor and L coil.

The resistors used in DC or AC circuits will always have the same resistance value, regardless of the feeding frequency.This is due to the fact that the resistors are classified purely with parasitic properties such as infinite capacitance C = ∞ and zero inductancy L = 0.In addition, the voltage and current for a resistant circuit are always in the same phase, so the power consumed at any given moment can be found by multiplying the voltage by the current at that moment.

Capacitors and inductors have a different type of AC resistance known as *reassurance* (X _{L} and X _{C).}The reassurance also blocks the flow of the current, but the amount of reassurance is not a fixed amount for an inductor or capacitor, in the same way that a resistance has a constant resistance value.The reactax value of an inductor or capacitor depends on the frequency of the feed current, as well as the DC value of the component.

Below is a list of passive components commonly used in AC circuits and their corresponding equations that can be used to find their values or circuit currents.Keep in mind that theoretically there is no resistance of an excellent (pure) capacitor or inductor.But in the real world, no matter how small, they will always have a resistance value.

### Fully Resistant Circuit

Resistance – Resistors regulate, block or adjust the flow of the current along a certain path, or apply a voltage drop in an electrical circuit as a result of this current flow.Resistors have *an* impedance called simply resistance (R), measured in Ω, the resistance value of a *resistance* Ohm.Resistors can have a constant value or a variable value (poenciometer).

### Fully Capacitive Circuit

Capacitor – The capacitor is a component capable or "capable" of storing energy in the form of an electric charge, such as a small battery.The capacitance value of a capacitor is measured in Farads, F.Dc has an infinite (open circuit) impedance (X _{C)} of a capacitor and a capacitor has zero impedance (short circuit) at very high frequencies.

### Fully Inductive Circuit

Inductor – An inductor is a wire coil that induces a magnetic field within itself or within a central nucleus as a direct result of the current passing through the coil.The induced value of an inductor is measured in Henry, H.In DC, an inductor has zero impedance (short circuit), while at high frequencies an inductor has an infinite (open circuit) impedance (X_{L).}

## Serial AC Circuits

Passive components in AC circuits can be connected in series combinations to create RC, RL and LC circuits, as shown.

### Serial RC Circuit

### Serial RL Circuit

### Serial LC Circuit

## Parallel AC Circuits

Passive components in AC circuits can also be connected in parallel combinations to create RC, RL and LC circuits, as shown.

### Parallel RC Circuit

### Parallel RL Circuit

### Parallel LC Circuit

## Passive RLC Circuits

All three passive components in AC circuits can be connected in both serial RLC and parallel RLC combinations, as shown below.

### Serial RLC Circuit

### Parallel RLC Circuit

Above, we found **that passive components in AC circuits**behave very differently than when connected to a DC circuit due to the effect of frequency (ε).In a fully resistant circuit, the current is in the same phase as the voltage.In a fully capacitive circuit, the current voltage in the capacitor is 90 ^{o }and in a completely inductive circuit the current voltage is 90^{o} behind.

Resistance to current flow from a passive component in an AC circuit is called: resistance, R for a resistance, XC for capacitor and inductive coloracency, XL for an inductor. The combination of resistance and reassurance is called impedance.

In a series of circuits, the phaser sum of voltages throughout the circuit components is equal to the supply voltage, V _{S.}In a parallel circuit, the phaser sum of the currents flowing in each branch and therefore in each of the circuit components is equal to the feed current, I _{S.}

For both parallel and serial connected RLC circuits, circuit **resonance **occurs as X _{L} = X _{C} when the feed current is in the "same phase" as the supply voltage.A Series Resonance Circuit is known as *the Receiver Circuit.*Parallel Resonance Circuit is known as *rejection circuit.*