An RLE Load consists of a Resistor ($R$), an Inductor ($L$), and a DC voltage source ($E$)—often representing a battery being charged or the back EMF of a DC motor. This configuration introduces unique constraints on the thyristor’s conduction compared to simpler loads. The Firing Constraint: Minimum Angle ($\theta_1$) Unlike R or RL loads, the …
Single-Phase Half-Wave Controlled Rectifier with RLE Load Read More »
In a standard $RL$ load rectifier, the inductor’s energy storage causes the output voltage to dip into the negative region, reducing the overall DC efficiency. By adding a Freewheeling Diode (FD) in parallel with the load, we can significantly enhance the circuit’s performance and protect the components. Why Use a Freewheeling Diode? The primary purpose …
Single-Phase Half-Wave Rectifier with RL Load and Freewheeling Diode (FD) Read More »
In power electronics, most real-world loads (like motors or transformers) are not purely resistive; they contain inductance. This article explores the Single Phase Half Wave Controlled Rectifier with an R-L Load, highlighting how inductance changes the behavior of the output voltage and current. The Role of Inductance ($L$) In a purely resistive load, the current …
Single Phase Half Wave Controlled Rectifier with an R-L Load Read More »
A Single Phase Half Wave Controlled Rectifier is a power electronics circuit used to convert an AC input into a variable DC output. By using a Thyristor (SCR) instead of a simple diode, we can control exactly when the conduction starts, allowing for precise voltage regulation. Circuit Components AC Source: Typically represented as $v_s = …
Single Phase Half Wave Controlled Rectifier with Resistive (R) Load Read More »
In the world of power electronics, few components are as critical as the thyristor. Often described as a “controllable diode,” this solid-state semiconductor device acts as a high-speed, bistable switch capable of handling massive voltages and currents. What is a Thyristor? A thyristor is a four-layer ($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 …
Blocked Rotor Test of Three Phase Induction Motor Read More »
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 …