## Impedance and Complex Impedance

In an Alternating Current, known commonly as an “AC circuit”, impedance is the opposition to current flowing around the circuit. Impedance is a value given in Ohms that is the combined effect of the circuits current limiting components within it, such as Resistance (R), Inductance (L), and Capacitance (C). In a Direct Current, or…

## Power Factor Correction

Power Factor Correction is a technique which uses capacitors to reduce the reactive power component of an AC circuit in order to improve its eficiency and reduce current. When dealing with direct current (DC) circuits, the power dissipated by the connected load is simply calculated as the product of the DC…

## Power in AC Circuits

In a DC circuit, the power consumed is simply the product of the DC voltage times the DC current, given in watts. However, for AC circuits with reactive components we have to calculate the consumed power differently. Electrical power is the “rate” at which energy is being consumed in a…

## Power Triangle and Power Factor

We saw in our tutorial about Electrical Power that AC circuits which contain resistance and capacitance or resistance and inductance, or both, also contain real power and reactive power. So in order for us to calculate the total power consumed, we need to know the phase difference between the sinusoidal waveforms of…

## Passive Components in AC Circuits

Electrical and electronic circuits consist of connecting together many different components to form a complete and closed circuit. The three main passive components used in any circuit are the: Resistor, the Capacitor and the Inductor. All three of these passive components have one thing in common, they limit the flow of electrical current through…

## Harmonics

In an AC circuit, a resistance behaves in exactly the same way as it does in a DC circuit. That is, the current flowing through the resistance is proportional to the voltage across it. This is because a resistor is a linear device and if the voltage applied to it…

## Reactive Power

In a DC circuit, the product of “volts x amps” gives the power consumed in watts by the circuit. However, while this formula is also true for purely resistive AC circuits, the situation is slightly more complex in an AC circuits containing reactive components as this volt-amp product can change…

## RMS Voltage Tutorial

In our tutorial about the AC Waveform we looked briefly at the RMS Voltage value of a sinusoidal waveform and said that this RMS value gives the same heating effect as an equivalent DC power and in this tutorial we will expand on this theory a little more by looking at RMS voltages and…

## Average Voltage Tutorial

The process used to find the Average Voltage of an alternating waveform is very similar to that for finding its RMS value, the difference this time is that the instantaneous values are not squared and we do not find the square root of the summed mean. The average voltage (or current) of…

## Parallel Resonance Circuit

In many ways a parallel resonance circuit is exactly the same as the series resonance circuit we looked at in the previous tutorial. Both are 3-element networks that contain two reactive components making them a second-order circuit, both are influenced by variations in the supply frequency and both have a frequency point…

## Series Resonance Circuit

Thus far we have analysed the behaviour of a series RLC circuit whose source voltage is a fixed frequency steady state sinusoidal supply. We have also seen in our tutorial about series RLC circuits that two or more sinusoidal signals can be combined using phasors providing that they have the…

## Series RLC Circuit Analysis

Thus far we have seen that the three basic passive components of: Resistance, Inductance, and Capacitance have very different phase relationships to each other when connected to a sinusoidal alternating supply. In a pure ohmic resistor the voltage waveforms are “in-phase” with the current. In a pure inductance the voltage waveform “leads” the current…