SCR – Silicon Controlled rectifier

A Silicon Controlled Rectifier (SCR) is a unidirectional semiconductor device that can be triggered into conduction by applying a positive gate current. It led to tremendous advancements in power semiconductor devices. They are also known as phase-control thyristors. They are high-speed semiconductor switching devices, similar to Shockley diodes but with an extra terminal. They generally … Read more

Transformer cooling methods

Transformers are the most efficient electric machine. A typical transformer is over 99% efficient. The small inefficiency is due to copper losses, core losses-hysteresis and eddy currents losses, stray and eddy current losses occurring in the transformer. These losses result in temperature rise. Various transformer cooling methods are adopted in order to maintain sufficient operating … Read more

Drawout circuit breaker positions and indications explained

Several operating indications can be seen on the front of an ACB or MCCB. Being an electrician or an engineer it is important that one must understand those indication and circuit breaker positions. Each of those indications has some critical information regarding the current state of the circuit breaker. The following are the three most … Read more

IGBT – Insulated Gate Bipolar Transistor

An insulated-gate bipolar transistor (IGBT) is a type of bipolar transistor that has an insulated gate terminal. The structure of the IGBT includes an input MOSFET which consists of the gate terminal and the output BJT consists of the collector and emitter terminals. The collector and emitter are the conduction terminals and the gate is … Read more

Common emitter configuration of BJT

The common emitter circuit is probably the most widely used transistor configuration. The emitter electrode is common to both input and output circuits. The common emitter amplifier has a typical input impedance of 1kilo ohms and a typical output impedance of 10 kilo-ohms. Also, the output will be the inverse of the input, which means … Read more

Difference between BJT and MOSFET

BJT and MOSFET are two types of semiconductor transistors. Even though both of them are transistors, they are different from each other in various aspects. By the end of this article, you will know the difference between BJT and MOSFET. Bipolar Junction Transistors (BJT) A Bipolar junction transistor, commonly known as BJT, by its construction, … Read more

MOSFET – Structure, working principle, symbol and applications

A Metal Oxide Semiconductor Field effect transistors, commonly known as MOSFET, are semiconductor switching devices that have three terminals which are the gate, drain and source. They are unipolar transistors, this means they depend on one type of charge carriers which can either be holes or electrons. They are much simpler to fabricate compared to … Read more

Types of Transformer windings

Transformer windings constitute the electrical circuit of a transformer. They are made up of current-carrying conductors wound around the core. The primary windings form the input to the transformer and the secondary windings form the output. The construction of the transformer windings should be stable enough to ensure safe operation. It should also be mechanically … Read more

Insulation materials used in transformers

Insulation materials are one of the most important elements in a transformer. They are used to electrically separate the conducting parts of a transformer from each other and from other components. Internal insulation failures are the major cause of transformer failures. This article intends to give you an overview of insulation materials used in transformers. … Read more

BJT – Bipolar Junction Transistors

A Bipolar junction transistor, commonly known as BJT, is a Si or Ge semiconductor device that is structured like two p-n junction diodes connected back to back. It has two outer regions which are the emitter and collector and another region in the middle known as the base. The bipolar junction transistor is called bipolar … Read more