Category: 2. Power Electronics

Rectification is the process of linking an AC power supply to a connected DC load by means of solid state semiconductor devices. Rectification converts an oscillating sinusoidal AC voltage source into a constant current DC voltage supply by means of diodes, thyristors, transistors, or converters. This rectifying process can take on many forms with half-wave,…

Solid State Relays are semiconductor equivalents of the electromechanical relay and can be used to control electrical loads without the use of moving parts. Unlike standard electro-mechanical relays and contactors which use coils, magnetic fields, springs and a variety of mechanical contacts to control and switch a power supply. The Solid State Relay, or SSR as it is…

Transient suppression devices can significantly reduce the amount of energy released as a result of over voltage spikes and surges. We would like to think that the AC or DC power supplies we use to power our circuits are both clean and well-regulated supplies. However, the switching of AC inductive loads or the switching of…

Linear voltage IC regulators have been the basis of power supply designs for many years as they are very good at supplying a continuous fixed voltage output. For a dedicated switch mode power supply, linear voltage regulators are generally much more efficient and easier to use than equivalent voltage regulator circuits made from discrete components…

The UJT is a three-terminal, semiconductor device which exhibits negative resistance and switching characteristics for use as a relaxation oscillator in phase control applications. The Unijunction Transistor or UJT for short, is another solid state three terminal device that can be used in gate pulse, timing circuits and trigger generator applications to switch and control either thyristors and triac’s…

The Diac is a two-junction bidirectional semiconductor device designed to break down when the AC voltage across it exceeds a certain level passing current in either direction. The Diode AC switch, or Diac for short, is another solid state, three-layer, two-junction semiconductor device but unlike the transistor the Diac has no base connection making it a two terminal device, labelled A1 and A2.…

The IGBT is a power switching transistor which combines the advantages of MOSFETs and BJTs for use in power supply and motor control circuits. The Insulated Gate Bipolar Transistor also called an IGBT for short, is something of a cross between a conventional Bipolar Junction Transistor, (BJT) and a Field Effect Transistor, (MOSFET) making it ideal as a semiconductor switching device.…

A Triac is a high-speed solid-state device that can switch and control AC power in both directions of a sinusoidal waveform. Both the thyristor and triac can be used to control lamps, motors, or heaters etc. However, one of the problems of using a thyristor for controlling such circuits is that like a diode, the…

Thyristors are high-speed solid-state devices which can be used to control motors, heaters and lamps. In the previous tutorial we looked at the basic construction and operation of the Silicon Controlled Rectifier more commonly known as a Thyristor. This time we will look at how we can use the thyristor and thyristor circuit to control…

In many ways the Silicon Controlled Rectifier, SCR or just Thyristor as it is more commonly known, is similar in construction to the transistor. In this thyristor tutorial we will look at the construction and operation of the thyristor, or Silicon Controlled Rectifier, (SCR) in more detail. In many ways the thyristor is similar in…