Principles Of Electronics By V.k.mehta

The heating current is passed through the heater and the cathode is heated indirectly through heat transfer from the heater element. An electronic device is that in which current flows through a vacuum or gas or semiconductor. For instance, in the circuit shown in Fig. Convert the constant current source in Fig.

The atomic structure of all known elements can be shown in this way and the reader is advised to try for a few commonly used elements. An important characteristic of alter- nating voltage source is that it periodically reverses the polarity of the output voltage. It may be seen that all points connected to chassis are shown as grounded and represent the same potential. In order to produce maximum power, the load e. Hope this post is helpful to you.

The Norton equivalent circuit will be as shown in Fig. However, if efficiency is more important e.

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Principles of electronics by v k mehta

Amazing easiest book for electronics student. Excellent book for persons who are freshly exposed to Electronics. In other words, horror ambience sound effects the metallic surface offers a barrier to free electrons and is known as surface barrier.

At room temperature, the thermal energy in the conductor is adequate to break the bonds of the valence electrons and leave them unattached to any one nucleus. How to select power inductors? This valuable property is utilised in television and radar.

Many electronic devices depend for their op- eration on the movement of electrons in an evacu- ated space. The purpose of this chapter is to present the elementary knowl- edge in order to enable the readers to follow the subsequent chapters. The original circuit of Fig. Comphrensive and good style of writing the technical comcepts. The greater the energy of a valence electron, the lesser it is bound to the nucleus.

For example, speed of a motor, voltage across a refrigerator etc. The emitted electrons are known as photo electrons and the phenomenon is known as photoelectric emission.

In our further discussion, we shall frequently use this scheme. In some electronic devices, however, secondary emission effects are utilised e. The term filament literally means a thin wire denotes the element through which the cathode heating current flows.

Principles of Electronics by V.K Mehta Rohit Mehta

Furthermore, because of relatively large mass of cylindrical cathode, it takes time to heat or cool and as such does not introduce hum due to heater voltage fluctuations. Electric power systems never operate for maximum power transfer because of low efficiency and high voltage drops between generated voltage and load. Now customize the name of a clipboard to store your clips. The principal limitation of this type of cathode is that any variation in heater voltage affects the electron emission and thus produces hum in the circuit.

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Electronic devices find wide applications in automatic control. This is shown in dotted line in Fig. The valence electrons which are very loosely attached to the nucleus are known as free electrons. At ordinary temperatures, the energy possessed by free electrons in the metal is inadequate to cause them to escape from the surface.

As cathode is completely separated from the heating circuit, therefore, it can be readily connected to any desired potential as needed, independent of the heater potential. Specially for Electronics and Electrical Engineer. These electrons are attracted by the positive anode to constitute current in the circuit. In the manufacture of this type of emitter, the base metal e.

The equivalent circuit of a d. It is clear that electrons in the last orbit possess very high energy as compared to the electrons in the inner orbits. Almost all modern receiving tubes use this type of cathode. These electrons also determine the electrical properties of a material. All the materials are composed of very small particles called atoms.

This will distort the output as well as increase the cost and size of equipment. The number of electrons emitted depends upon the temperature. When heat is applied to the metal, some of heat energy is converted into kinetic energy, causing accelerated motion of free electrons.

The number of electrons or protons in an atom is called atomic number i. When the temperature rises sufficiently, these electrons acquire additional energy equal to the work function of the metal. Thank you for visiting my thread.

Thus, it depends upon a particular situation as to what the load should be. It is clear that current remains con- stant even when the output voltage changes substantially.

You can change your ad preferences anytime. You just clipped your first slide! SlideShare Explore Search You. In any vacuum tube, no matter how careful the evacuation, there are always present some gas molecules which may form ions by impact with electrons when current flows. Kindly share this post with your friends to make this exclusive release more useful.

The atoms are the building bricks of all matter. Convert the current source in Fig. Maximum power is transferred from a source to a load when the load resistance is made equal to the internal resistance of the source. It is because the particles in the extra nucleus i. The amplifiers are used in a wide variety of ways.

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