Gas Filled Tubes | Conduction in a Gas

INTRODUCTION OF GAS-FILLED TUBE In the vacuum tubes, the electrons pass from the cathode to anode in a vacuum. In that type of tubes, extreme care is taken to generate as perfect a vacuum as possible to prevent ionization of gases and the resulting large uncontrolled currents. It may be mentioned here that the logic … Read more

Cold Cathode Gas Diode | Applications of Glow Tubes

Cold-Cathode Gas Diode Fig. 3.6 shows the cut-away view of the cold-cathode gas diode. It essentially has two electrodes, anode, and cathode mounted fairly close to each other in an envelope filled with few inert gases at small pressure. The anode is in the shape of a thin wire whereas cathode is of the cylindrical … Read more

Thyratron | Hot Cathode Gas Diode | Applications of Thyratron

Hot-Cathode Gas Diode A hot-cathode gas diode is mostly used as a rectifier for moderate voltages because of large efficiency and good regulation. A hot-cathode gas diode having an oxide-coated cathode and a metallic anode enclosed in a glass envelope containing few inert gases under low pressure. For proper operation of the tube, the anode … Read more

Energy Bands | Bohr’s Atomic Model | Energy Levels | Silicon

INTRODUCTION The study of the atomic structure and energy bands is the most important for electronics engineering. The fact is that the size of an atom is so small that it is virtually not possible to see it even with the most powerful microscope. Therefore, we have to employ an indirect method for the knowledge … Read more

What is Semiconductor | Effect of Temperature on Semiconductors

INTRODUCTION Semiconductor:- Materials such as germanium, silicon, carbon, etc. are not good conductors like copper nor insulators like glass. In other words, the resistivity of these substances lies in between conductors and insulators. Such materials are known as semiconductors. Semiconductors have some useful characteristics and are being extensively used in electronics devices. For instance, a … Read more

Hole Current | Intrinsic & Extrinsic Semiconductor

What is Hole Current ? At Normal room temperature, few of the covalent bonds in pure semiconductor material break, setting up free electrons. Under the effect of the electric field, these free electrons constitute an electric current. At the same time, another current – the hole current – also flows in the semiconductor. When a … Read more

What is PN Junction | Properties of PN Junction

What is PN junction ? When a p-type semiconductor is suitably joined to n-type semiconductors, the contact surface is called PN junction. Most semiconductor devices contain one or more PN junctions. The PN junction is of great importance because it is in effect, the control element for semiconductor devices. Thorough knowledge of the formation and … Read more

what is Semiconductor Diode | Properties of Diode

What is Semiconductor Diode It has already been discussed in the previous article that a pn junction conducts current easily when forward biased and practically no current flows when it is reverse biased. This unilateral conduction characteristic of pn junction (i.e. semiconductor diode) is similar to that of a vacuum diode. Therefore, like a vacuum … Read more

Faults in Centre Tap Full Wave Rectifier

Faults in Centre Tap Full Wave Rectifier The faults in a center tap full-wave rectifier may occur in the transformer or rectifier diodes. Fig.6.36 shows the circuit of a center-tap full-wave rectifier. A fuse is connected in the primary of the transformer for protection purposes. We can divide the rectifier faults into two classes viz. … Read more

Nature of Rectifier Output | Ripple Factor | Comparison of Rectifiers

Nature of Rectifier Output Nature of Rectifier:- It has already been discussed that the output of a rectifier is pulsating d.c. as shown in Fig. 6.37. In fact, if such a waveform is carefully analyzed, it will be found that it contains a d.c. component and an a.c. component. The a.c. the component is responsible … Read more