Power Converter – Definition and Classification

Power Converter – Definition and Classification: Solid-state power converter are employed for obtaining the appro­priate form of electrical energy such as direct current or adjustable-frequency alternating current (required to operate most electronic circuits and motor drives) from fixed-frequency alternating current. Classification of Static Power Converter: AC/DC converters, AC/AC converters, DC/DC converters and DC/AC converters. AC/DC …

Power Converter – Definition and Classification Read More »

UJT Relaxation Oscillator – Circuit Diagram and its Workings

UJT Relaxation Oscillator – Circuit Diagram and its Workings: UJT Relaxation Oscillator – The relaxation oscillator shown in Fig. 26.94 (a) consists of UJT and a capacitor C which is charged through resistor RE when interbase voltage VBB is switched on. During the charging pe­riod, the voltage across the capacitor increases exponentially until it attains …

UJT Relaxation Oscillator – Circuit Diagram and its Workings Read More »

Power BJT – Construction, Operation and its Characteristics

Power BJT – Construction, Operation and its Characteristics: Power transistors are large-area devices. Because of differences in geometry and doping concentrations, their properties tend to vary from those of the small-signal devices. The structure of a vertical NPN power transistor is shown in Fig. 26.74. In the vertical con­figuration for power BJT, the collector terminal …

Power BJT – Construction, Operation and its Characteristics Read More »

Light Activated SCR (LASCR) – Symbol, Construction and Operation

Light Activated SCR (LASCR) – Symbol, Construction and Operation: Light activated SCR is just an ordinary SCR except that it can also be light triggered. Most LASCRs also have a gate terminal for be­ing triggered by an electrical pulse just as a conventional SCR. Construction: The basic construction of an Light Activated SCR (LASCR) is …

Light Activated SCR (LASCR) – Symbol, Construction and Operation Read More »

Silicon Controlled Switch (SCS) – Symbol, Operation, Advantages and Application

Silicon Controlled Switch (SCS) – Symbol, Operation, Advantages and Application: Silicon controlled switch (SCS), like the SCR, is a unilateral, four layer, three junction P-N-P-N silicon device with four electrodes namely cathode C, cathode gate G1, anode gate G2 and the anode A, as shown in Fig. 26.59. Infact, the Silicon Controlled Switch is a …

Silicon Controlled Switch (SCS) – Symbol, Operation, Advantages and Application Read More »

Gate Controlled Switch (GCS) Circuit Operation and Advantages

Gate Controlled Switch (GCS) Circuit Operation and Advantages: As mentioned earlier, low-current drop out is the normal way in which the SCR is turned off. Gate controlled switch is designed for easy opening with a reverse-biased trigger. A GCS is closed by a positive trigger and opened by a negative trigger (or by low-current drop out). …

Gate Controlled Switch (GCS) Circuit Operation and Advantages Read More »

What is Shockley Diode? – Symbol, Operation and Applications

What is Shockley Diode? – Symbol, Operation and Applications The four layer diode, also called the Shockley diode after its in­ventor Willian Shockley, is essentially a low-current SCR without a gate. It is classified as a diode because it has only two exter­nal terminals viz. anode and cathode. Because of its four doped regions, it …

What is Shockley Diode? – Symbol, Operation and Applications Read More »