Fluid mechanics is the study of how fluids (liquids and gases) behave and interact under various forces and in various applied situations. Some key topics in fluid mechanics include: Fluid statics, which deals with fluids at rest Fluid dynamics, which deals with fluids in motion Bernoulli’s equation, which relates pressure, velocity, and height in a … Read more
Buoyant Force Buoyant force is the upward force exerted on an object by a fluid, such as water or air, when the object is placed in the fluid. This force is what allows objects to float or rise to the surface of a fluid. The buoyant force on an object is equal to the weight … Read more
Photonic p-n junction devices The p-n junctions can be designed so that current through them changes either by causing electron excitation (from valence band to the conduction band) by light photons, or conversely through electron excitation by a suitable bias voltage resulting in the emission of light photons. These semiconducting devices are called photonic or … Read more
Zener diode: A junction diode specially designed to operate only in the reverse breakdown region continuously (without getting damaged) is called a Zener diode. Zener diodes with different breakdown voltages can be obtained by changing the doping concentrations of p- and n-sides which, in turn, change the width of depletion layer and also the barrier … Read more
Filter circuits: The output obtained from a junction diode rectifier is unidirectional but pulsating. Such a signal can be considered as the sum of a d.c. signal superimposed with many a.c. signals of different harmonic frequencies. We can obtain d.c. voltage by filtering out the a.c. components. We describe here two simplest filter circuits. 1. … Read more
Junction diode as a full wave rectifier: A full wave rectifier consists of a transformer, two junction diodes D1 and D2 and a load resistance RL. The input a.c. signal is fed to the primary coil P of the transformer. The two ends A and B of the secondary S are connected to the p-ends … Read more
Junction diode as a half-wave rectifier: A half-wave rectifier consists of a transformer, a junction diode D and a load resistance RL. Tire primary coil of the transformer is connected to the a.c. mains and the secondary coil is connected in series with the junction diode D and load resistance RL. We assume that the … Read more
Holes: The vacancy or absence of an electron in the bond of a covalently bonded crystal is called a hole. In terms of band theory, whenever an electron is removed from the completely filled valence band of a semiconductor, a vacancy is left behind in the valence band. This vacancy serves as a positive charge … Read more
Classification of semiconductors On the basis of their chemical composition. This scheme divides semiconductors broadly into elemental and compound semiconductors. A. Elemental semiconductors: Si and Ge. B. Compound semiconductors: Examples are: (i) Inorganic: CdS, GaAs, CdSe, InP, etc. (ii) Organic polymers: Polypyrrole, polyaniline, polythiophene, etc. Both elemental and compound inorganic semiconductors are being largely used. … Read more
Electronic Devices The discovery of the electron was a landmark in physics and has led to a great technological advance. The present-day instant communication with the entire world is the result of the multifarious uses of these electrons. As an electron is a light particle having a negative charge, so it can be easily manipulated … Read more
