In the world of power electronics, few components are as critical as the thyristor. Often described as a “controllable diode,” this solid-state semiconductor device acts as a high-speed, bistable switch capable of handling massive voltages and currents. What is a Thyristor? A thyristor is a four-layer ($P-N-P-N$) semiconductor device with three junctions ($J_1, J_2,$ and …
In power electronics, the Unijunction Transistor (UJT) Relaxation Oscillator is a classic circuit used to generate sawtooth waveforms and trigger pulses for SCRs and TRIACs. Its beauty lies in its simplicity, requiring only a handful of components to create a repetitive switching cycle. How it Works The circuit operates by exploiting the negative resistance characteristic …
The Bipolar Junction Transistor, commonly known as the BJT, is one of the most significant inventions in the history of electronics. Before the rise of the modern Field Effect Transistor (FET), the BJT was the undisputed king of amplification and switching. Even today, it remains a cornerstone of analog circuit design due to its high …
An HVDC (High Voltage Direct Current) system is an advanced power transmission technology that uses power electronics to transmit large amounts of electrical energy over long distances in the form of direct current (DC). Although most power systems generate and distribute electricity as alternating current (AC), HVDC systems are widely used for bulk power transfer …
The blocked-rotor test of a squirrel-cage induction motor is an important experiment used to determine leakage reactance, resistance, and short-circuit characteristics of the motor. It is performed by locking the rotor and applying a reduced voltage to the stator. The main objective is to determine equivalent circuit parameters such as stator resistance, rotor resistance (referred …
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A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is the most widely used transistor in modern electronics. It acts as a voltage-controlled switch that can turn circuits ON or OFF without any moving parts. It is used in devices like smartphones to high-power industrial motor controllers. Working Source (S): Where electrons enter (like water source) Drain (D): Where …
A PN junction diode is formed by joining two types of semiconductor materials: P-type semiconductor → rich in holes (positive charge carriers) N-type semiconductor → rich in electrons (negative charge carriers) When these two regions are joined, a junction is formed called the PN junction. As soon as the P and N regions are joined, …
Gauss’s Law is one of the fundamental laws of electromagnetism. It provides a simple way to calculate the electric field generated by a distribution of charge, especially when the distribution is symmetrical. In simple terms, Gauss’s Law states that the total electric flux (the flow of electric field lines) passing through any closed surface is …
An Electric Dipole Moment is a physical quantity used to describe the strength and orientation of an electric dipole, which consists of two equal and opposite charges separated by a distance. Consider two charges: a positive charge \(+q\) and a negative charge \(-q\), separated by a distance \(d\). The dipole moment \(\mathbf{p}\) represents how far …
To solve AC circuit problems, you need to understand the concept of the Power Triangle, which relates three types of power using trigonometry. Think of an AC circuit like a “latte”: the liquid is the useful energy doing work, while the foam represents extra power that does not perform useful work. Active Power (P): The …