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# Alternating Current (AC)

## Capacitor and the Alternating Current

Capacitor and the Alternating Current

Unlike the behavior of a capacitor in direct current (DC), the alternating current (AC) passes more easily through a capacitor.

## Ideal Transformer Working Principle

Ideal Transformer

The ideal transformer is an electromagnetic device that allows to increase or decrease the alternating voltage and current while maintaining constant the power

## Power Factor Definition (PF) – Power Factor Formulas

Power Factor Definition

Power factor is the ratio between the energy that is converted into work and the electrical energy consumed in a circuit or device

## The Core-laminated Transformer – Why is a Transformer Core-laminated?

The Core-laminated Transformer – Why is a Transformer Core-laminated?

Why it is not possible to use a solid iron core instead of core-laminated? What is Eddy or Foucault’s currents?

## Half Wave Rectifier – Half-wave Rectifier. Circuit diagram

The half-wave rectifier rectification process.

Polarization of semiconductor diode in the forward and in the reverse direction. Input and output waveforms

## Push – Pull Amplifier – Push – Pull Amplifier Operation

Push – Pull Amplifier

A Push – Pull amplifier is called that way, because it uses 2 groups of transistors and only one works at a time. One group pushes in one direction while the other pulls in another direction. Each group is responsible for amplifying a single phase of the input wave.

## Parallel RC circuit

Parallel RC circuit

Voltage, Currents, Phasor diagram & Impedance. Voltage is the same on the capacitor and resistor. Current is ahead of the voltage in the capacitor

## Sinusoidal oscillator (basic structure)

Basic structure of the sinusoidal oscillator

The sinusoidal oscillator basic structure consists of an amplifier (A) and a selective frequency network (ß) connected in a positive feedback loop

## Series RC circuit connected to an AC voltage

The series RC circuit.

In a series RC circuit, the current through the resistor and the capacitor is the same. The voltage VS is equal to the phasor addition of the voltage drop across the resistor (Vr) and the voltage drop across the capacitor (Vc).

## Air core inductor inductance calculation

Air core inductor coil inductance calculation

There are some occasions when we have an air core inductor, and we don’t know what its value is. There is an easy way to obtain the air core inductor coil inductance if you have the external measurements of this component.

## Power Transformer usage

The Electric Power Transformer usage – The Transformer Distribution System

Electric power transformers are static electrical machines that allows modification of the voltage and the current values, so they can take the appropriate one (value) to carry and distribute the electric energy.

## Properties of the Alternating Current (AC)

What is Alternating Current?

The difference between an alternating current and a continuous current is that the continuous current flows only on one direction. The alternating current circulates first in one direction and then on the opposite one, repeating this process continuously.

## Iron Core Inductor

Iron Core Inductor

The iron core has very special magnetic characteristics. What they do is to reinforce the magnetic field. The magnetism of the core material depends on the bias of  “the molecular magnetic domains”

## Resonance in an RLC Circuit (electrical resonance)

What is Resonance in RLC Circuits?

Resonance in RLC Circuits is a special condition for parallel and series RLC circuits, when capacitive reactance and inductive reactance have the same magnitude and cancel each other. This only happens at frequency fo.

## Impedance of Inductor

What is the Impedance of an Inductor?

The impedance of an inductor (also called inductance) is the measure of the opposition to a change of electrical current in this component.

## Power in an Alternating Current Circuit

Power in AC circuits.

Electric power. Electrical power on a circuit with reactive load (reactance).

How to obtain the current in a circuit having resistance and reactance.

## Transformer Structure

Electric Power Transformer Structure

All electric transformers regardless of their size, have three fundamentals parts: high voltage winding, low voltage winding and Core:

## Autotransformer

What is an Autotransformer?

An autotransformer is a transformer where a part of the winding belongs to both the primary and secondary windings of the transformer. The operating principle is the same as the conventional transformer.

## Impedance (Z) = (Resistance + Reactance)

What is Impedance?

Impedance (Z) shows the opposition to the flow of direct or alternating current. Impedance is the vectorial addition of resistance (R) and reactance (X).

## Transformer Turn Ratio (TTR)

Transformer Turn Ratio – Transformer Transformation Ratio (TTR)

The transformer transformation ratio or transformer turns ratio (K) is the quotient value obtained by dividing the number of turns of the primary winding (N1) and the number of turns of the secondary winding (N2). Then K = N1/N2.

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